1
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Banayan NE, Loughlin BJ, Singh S, Forouhar F, Lu G, Wong K, Neky M, Hunt HS, Bateman LB, Tamez A, Handelman SK, Price WN, Hunt JF. Systematic enhancement of protein crystallization efficiency by bulk lysine-to-arginine (KR) substitution. Protein Sci 2024; 33:e4898. [PMID: 38358135 PMCID: PMC10868448 DOI: 10.1002/pro.4898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 01/01/2024] [Accepted: 01/02/2024] [Indexed: 02/16/2024]
Abstract
Structural genomics consortia established that protein crystallization is the primary obstacle to structure determination using x-ray crystallography. We previously demonstrated that crystallization propensity is systematically related to primary sequence, and we subsequently performed computational analyses showing that arginine is the most overrepresented amino acid in crystal-packing interfaces in the Protein Data Bank. Given the similar physicochemical characteristics of arginine and lysine, we hypothesized that multiple lysine-to-arginine (KR) substitutions should improve crystallization. To test this hypothesis, we developed software that ranks lysine sites in a target protein based on the redundancy-corrected KR substitution frequency in homologs. This software can be run interactively on the worldwide web at https://www.pxengineering.org/. We demonstrate that three unrelated single-domain proteins can tolerate 5-11 KR substitutions with at most minor destabilization, and, for two of these three proteins, the construct with the largest number of KR substitutions exhibits significantly enhanced crystallization propensity. This approach rapidly produced a 1.9 Å crystal structure of a human protein domain refractory to crystallization with its native sequence. Structures from Bulk KR-substituted domains show the engineered arginine residues frequently make hydrogen-bonds across crystal-packing interfaces. We thus demonstrate that Bulk KR substitution represents a rational and efficient method for probabilistic engineering of protein surface properties to improve crystallization.
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Affiliation(s)
- Nooriel E. Banayan
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Blaine J. Loughlin
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Shikha Singh
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Farhad Forouhar
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Guanqi Lu
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Kam‐Ho Wong
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
Vaccine Research and DevelopmentPfizer Inc.Pearl RiverNew YorkUSA
| | - Matthew Neky
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
Columbia UniversityNew YorkNew YorkUSA
| | - Henry S. Hunt
- Department of PhysicsStanford UniversityStanfordCaliforniaUSA
| | | | | | - Samuel K. Handelman
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
Department of Pain & Neuronal HealthEli Lily & Co.893 Delaware StIndianapolisIndianaUSA
| | - W. Nicholson Price
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
University of Michigan Law SchoolAnn ArborMichiganUSA
| | - John F. Hunt
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
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2
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Ousalem F, Singh S, Bailey NA, Wong KH, Zhu L, Neky MJ, Sibindi C, Fei J, Gonzalez RL, Boël G, Hunt JF. Comparative genetic, biochemical, and biophysical analyses of the four E. coli ABCF paralogs support distinct functions related to mRNA translation. bioRxiv 2023:2023.06.11.543863. [PMID: 37398404 PMCID: PMC10312648 DOI: 10.1101/2023.06.11.543863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Multiple paralogous ABCF ATPases are encoded in most genomes, but the physiological functions remain unknown for most of them. We herein compare the four Escherichia coli K12 ABCFs - EttA, Uup, YbiT, and YheS - using assays previously employed to demonstrate EttA gates the first step of polypeptide elongation on the ribosome dependent on ATP/ADP ratio. A Δ uup knockout, like Δ ettA , exhibits strongly reduced fitness when growth is restarted from long-term stationary phase, but neither Δ ybiT nor Δ yheS exhibits this phenotype. All four proteins nonetheless functionally interact with ribosomes based on in vitro translation and single-molecule fluorescence resonance energy transfer experiments employing variants harboring glutamate-to-glutamine active-site mutations (EQ 2 ) that trap them in the ATP-bound conformation. These variants all strongly stabilize the same global conformational state of a ribosomal elongation complex harboring deacylated tRNA Val in the P site. However, EQ 2 -Uup uniquely exchanges on/off the ribosome on a second timescale, while EQ 2 -YheS-bound ribosomes uniquely sample alternative global conformations. At sub-micromolar concentrations, EQ 2 -EttA and EQ 2 -YbiT fully inhibit in vitro translation of an mRNA encoding luciferase, while EQ 2 -Uup and EQ 2 -YheS only partially inhibit it at ~10-fold higher concentrations. Moreover, tripeptide synthesis reactions are not inhibited by EQ 2 -Uup or EQ 2 -YheS, while EQ 2 -YbiT inhibits synthesis of both peptide bonds and EQ 2 -EttA specifically traps ribosomes after synthesis of the first peptide bond. These results support the four E. coli ABCF paralogs all having different activities on translating ribosomes, and they suggest that there remains a substantial amount of functionally uncharacterized "dark matter" involved in mRNA translation.
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3
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Li Y, Zhang R, Wang C, Forouhar F, Clarke OB, Vorobiev S, Singh S, Montelione GT, Szyperski T, Xu Y, Hunt JF. Oligomeric interactions maintain active-site structure in a noncooperative enzyme family. EMBO J 2022; 41:e108368. [PMID: 35801308 DOI: 10.15252/embj.2021108368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 04/07/2022] [Accepted: 04/16/2022] [Indexed: 11/09/2022] Open
Abstract
The evolutionary benefit accounting for widespread conservation of oligomeric structures in proteins lacking evidence of intersubunit cooperativity remains unclear. Here, crystal and cryo-EM structures, and enzymological data, demonstrate that a conserved tetramer interface maintains the active-site structure in one such class of proteins, the short-chain dehydrogenase/reductase (SDR) superfamily. Phylogenetic comparisons support a significantly longer polypeptide being required to maintain an equivalent active-site structure in the context of a single subunit. Oligomerization therefore enhances evolutionary fitness by reducing the metabolic cost of enzyme biosynthesis. The large surface area of the structure-stabilizing oligomeric interface yields a synergistic gain in fitness by increasing tolerance to activity-enhancing yet destabilizing mutations. We demonstrate that two paralogous SDR superfamily enzymes with different specificities can form mixed heterotetramers that combine their individual enzymological properties. This suggests that oligomerization can also diversify the functions generated by a given metabolic investment, enhancing the fitness advantage provided by this architectural strategy.
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Affiliation(s)
- Yaohui Li
- Key Laboratory of Industrial Biotechnology of Ministry of Education and School of Biotechnology, Jiangnan University, Wuxi, China.,Department of Biological Sciences, 702 Sherman Fairchild Center, MC2434, Columbia University, New York, NY, USA
| | - Rongzhen Zhang
- Key Laboratory of Industrial Biotechnology of Ministry of Education and School of Biotechnology, Jiangnan University, Wuxi, China
| | - Chi Wang
- Department of Biological Sciences, 702 Sherman Fairchild Center, MC2434, Columbia University, New York, NY, USA.,Cryo-Electron Microscopy Center, Columbia University Irving Medical Center, New York, NY, USA
| | - Farhad Forouhar
- Department of Biological Sciences, 702 Sherman Fairchild Center, MC2434, Columbia University, New York, NY, USA.,Macromolecular Crystallography Shared Resource, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics and Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA
| | - Sergey Vorobiev
- Department of Biological Sciences, 702 Sherman Fairchild Center, MC2434, Columbia University, New York, NY, USA
| | - Shikha Singh
- Department of Biological Sciences, 702 Sherman Fairchild Center, MC2434, Columbia University, New York, NY, USA
| | - Gaetano T Montelione
- Department of Chemistry & Chemical Biology and Center for Biotechnology & Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Thomas Szyperski
- Department of Chemistry, State University of New York at Buffalo, Buffalo, NY, USA
| | - Yan Xu
- Key Laboratory of Industrial Biotechnology of Ministry of Education and School of Biotechnology, Jiangnan University, Wuxi, China
| | - John F Hunt
- Department of Biological Sciences, 702 Sherman Fairchild Center, MC2434, Columbia University, New York, NY, USA
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4
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Patil DN, Singh S, Laboute T, Strutzenberg TS, Qiu X, Wu D, Novick SJ, Robinson CV, Griffin PR, Hunt JF, Izard T, Singh AK, Martemyanov KA. Cryo-EM structure of human GPR158 receptor coupled to the RGS7-Gβ5 signaling complex. Science 2022; 375:86-91. [PMID: 34793198 PMCID: PMC8926151 DOI: 10.1126/science.abl4732] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
GPR158 is an orphan G protein–coupled receptor (GPCR) highly expressed in the brain, where it controls synapse formation and function. GPR158 has also been implicated in depression, carcinogenesis, and cognition. However, the structural organization and signaling mechanisms of GPR158 are largely unknown. We used single-particle cryo–electron microscopy (cryo-EM) to determine the structures of human GPR158 alone and bound to an RGS signaling complex. The structures reveal a homodimeric organization stabilized by a pair of phospholipids and the presence of an extracellular Cache domain, an unusual ligand-binding domain in GPCRs. We further demonstrate the structural basis of GPR158 coupling to RGS7-Gβ5. Together, these results provide insights into the unusual biology of orphan receptors and the formation of GPCR-RGS complexes.
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Affiliation(s)
- Dipak N. Patil
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Shikha Singh
- Department of Biological Sciences, Columbia University New York, NY 10027
| | - Thibaut Laboute
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | | | - Xingyu Qiu
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,The Kavli Institute for Nanoscience Discovery, Oxford, OX1 3QU, UK
| | - Di Wu
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,The Kavli Institute for Nanoscience Discovery, Oxford, OX1 3QU, UK
| | - Scott J. Novick
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Carol V. Robinson
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,The Kavli Institute for Nanoscience Discovery, Oxford, OX1 3QU, UK
| | - Patrick R. Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - John F. Hunt
- Department of Biological Sciences, Columbia University New York, NY 10027
| | - Tina Izard
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Appu K. Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India,Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India,Co-corresponding authors: Dr. Kirill A. Martemyanov, ; Dr. Appu K. Singh,
| | - Kirill A. Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA,Co-corresponding authors: Dr. Kirill A. Martemyanov, ; Dr. Appu K. Singh,
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5
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Bahia MS, Khazanov N, Zhou Q, Yang Z, Wang C, Hong JS, Rab A, Sorscher EJ, Brouillette CG, Hunt JF, Senderowitz H. Stability Prediction for Mutations in the Cytosolic Domains of Cystic Fibrosis Transmembrane Conductance Regulator. J Chem Inf Model 2021; 61:1762-1777. [PMID: 33720715 DOI: 10.1021/acs.jcim.0c01207] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cystic Fibrosis (CF) is caused by mutations to the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) chloride channel. CFTR is composed of two membrane spanning domains, two cytosolic nucleotide-binding domains (NBD1 and NBD2) and a largely unstructured R-domain. Multiple CF-causing mutations reside in the NBDs and some are known to compromise the stability of these domains. The ability to predict the effect of mutations on the stability of the cytosolic domains of CFTR and to shed light on the mechanisms by which they exert their effect is therefore important in CF research. With this in mind, we have predicted the effect on domain stability of 59 mutations in NBD1 and NBD2 using 15 different algorithms and evaluated their performances via comparison to experimental data using several metrics including the correct classification rate (CCR), and the squared Pearson correlation (R2) and Spearman's correlation (ρ) calculated between the experimental ΔTm values and the computationally predicted ΔΔG values. Overall, the best results were obtained with FoldX and Rosetta. For NBD1 (35 mutations), FoldX provided R2 and ρ values of 0.64 and -0.71, respectively, with an 86% correct classification rate (CCR). For NBD2 (24 mutations), FoldX R2, ρ, and CCR were 0.51, -0.73, and 75%, respectively. Application of the Rosetta high-resolution protocol (Rosetta_hrp) to NBD1 yielded R2, ρ, and CCR of 0.64, -0.75, and 69%, respectively, and for NBD2 yielded R2, ρ, and CCR of 0.29, -0.27, and 50%, respectively. The corresponding numbers for the Rosetta's low-resolution protocol (Rosetta_lrp) were R2 = 0.47, ρ = -0.69, and CCR = 69% for NBD1 and R2 = 0.27, ρ = -0.24, and CCR = 63% for NBD2. For NBD1, both algorithms suggest that destabilizing mutations suffer from destabilizing vdW clashes, whereas stabilizing mutations benefit from favorable H-bond interactions. Two triple consensus approaches based on FoldX, Rosetta_lpr, and Rosetta_hpr were attempted using either "majority-voting" or "all-voting". The all-voting consensus outperformed the individual predictors, albeit on a smaller data set. In summary, our results suggest that the effect of mutations on the stability of CFTR's NBDs could be largely predicted. Since NBDs are common to all ABC transporters, these results may find use in predicting the effect and mechanism of the action of multiple disease-causing mutations in other proteins.
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Affiliation(s)
| | - Netaly Khazanov
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Qingxian Zhou
- School of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Zhengrong Yang
- School of Medicine, Division of Hematology & Oncology, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Chi Wang
- 702 Fairchild Center, MC3423, Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Jeong S Hong
- Department of Paediatrics, Emory University School of Medicine, Atlanta, Georgia 30303, United States
| | - Andras Rab
- Department of Paediatrics, Emory University School of Medicine, Atlanta, Georgia 30303, United States
| | - Eric J Sorscher
- Department of Paediatrics, Emory University School of Medicine, Atlanta, Georgia 30303, United States
| | - Christie G Brouillette
- Department of Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - John F Hunt
- 702 Fairchild Center, MC3423, Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Hanoch Senderowitz
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
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6
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Mehla J, Liechti G, Morgenstein RM, Caufield JH, Hosseinnia A, Gagarinova A, Phanse S, Goodacre N, Brockett M, Sakhawalkar N, Babu M, Xiao R, Montelione GT, Vorobiev S, den Blaauwen T, Hunt JF, Uetz P. ZapG (YhcB/DUF1043), a novel cell division protein in gamma-proteobacteria linking the Z-ring to septal peptidoglycan synthesis. J Biol Chem 2021; 296:100700. [PMID: 33895137 PMCID: PMC8163987 DOI: 10.1016/j.jbc.2021.100700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/14/2021] [Accepted: 04/21/2021] [Indexed: 01/26/2023] Open
Abstract
YhcB, a poorly understood protein conserved across gamma-proteobacteria, contains a domain of unknown function (DUF1043) and an N-terminal transmembrane domain. Here, we used an integrated approach including X-ray crystallography, genetics, and molecular biology to investigate the function and structure of YhcB. The Escherichia coli yhcB KO strain does not grow at 45 °C and is hypersensitive to cell wall–acting antibiotics, even in the stationary phase. The deletion of yhcB leads to filamentation, abnormal FtsZ ring formation, and aberrant septum development. The Z-ring is essential for the positioning of the septa and the initiation of cell division. We found that YhcB interacts with proteins of the divisome (e.g., FtsI, FtsQ) and elongasome (e.g., RodZ, RodA). Seven of these interactions are also conserved in Yersinia pestis and/or Vibrio cholerae. Furthermore, we mapped the amino acid residues likely involved in the interactions of YhcB with FtsI and RodZ. The 2.8 Å crystal structure of the cytosolic domain of Haemophilus ducreyi YhcB shows a unique tetrameric α-helical coiled-coil structure likely to be involved in linking the Z-ring to the septal peptidoglycan-synthesizing complexes. In summary, YhcB is a conserved and conditionally essential protein that plays a role in cell division and consequently affects envelope biogenesis. Based on these findings, we propose to rename YhcB to ZapG (Z-ring-associated protein G). This study will serve as a starting point for future studies on this protein family and on how cells transit from exponential to stationary survival.
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Affiliation(s)
- Jitender Mehla
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA.
| | - George Liechti
- Department of Microbiology and Immunology, Henry Jackson Foundation, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Randy M Morgenstein
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - J Harry Caufield
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Ali Hosseinnia
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Alla Gagarinova
- Department of Biochemistry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Sadhna Phanse
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Norman Goodacre
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Mary Brockett
- Department of Microbiology and Immunology, Henry Jackson Foundation, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Neha Sakhawalkar
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Rong Xiao
- Nexomics Biosciences Inc., Rocky Hill, New Jersey, USA; Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Gaetano T Montelione
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA; Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Sergey Vorobiev
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA; Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Tanneke den Blaauwen
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - John F Hunt
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA; Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Peter Uetz
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA.
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7
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Fostier CR, Monlezun L, Ousalem F, Singh S, Hunt JF, Boël G. ABC-F translation factors: from antibiotic resistance to immune response. FEBS Lett 2020; 595:675-706. [PMID: 33135152 DOI: 10.1002/1873-3468.13984] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 12/24/2022]
Abstract
Energy-dependent translational throttle A (EttA) from Escherichia coli is a paradigmatic ABC-F protein that controls the first step in polypeptide elongation on the ribosome according to the cellular energy status. Biochemical and structural studies have established that ABC-F proteins generally function as translation factors that modulate the conformation of the peptidyl transferase center upon binding to the ribosomal tRNA exit site. These factors, present in both prokaryotes and eukaryotes but not in archaea, use related molecular mechanisms to modulate protein synthesis for heterogenous purposes, ranging from antibiotic resistance and rescue of stalled ribosomes to modulation of the mammalian immune response. Here, we review the canonical studies characterizing the phylogeny, regulation, ribosome interactions, and mechanisms of action of the bacterial ABC-F proteins, and discuss the implications of these studies for the molecular function of eukaryotic ABC-F proteins, including the three human family members.
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Affiliation(s)
- Corentin R Fostier
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
| | - Laura Monlezun
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
| | - Farès Ousalem
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
| | - Shikha Singh
- Department of Biological Sciences, 702A Sherman Fairchild Center, Columbia University, New York, NY, USA
| | - John F Hunt
- Department of Biological Sciences, 702A Sherman Fairchild Center, Columbia University, New York, NY, USA
| | - Grégory Boël
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
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8
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Kleizen B, Hunt JF, Callebaut I, Hwang TC, Sermet-Gaudelus I, Hafkemeyer S, Sheppard DN. CFTR: New insights into structure and function and implications for modulation by small molecules. J Cyst Fibros 2020; 19 Suppl 1:S19-S24. [DOI: 10.1016/j.jcf.2019.10.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/22/2022]
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9
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Grime GW, Zeldin OB, Snell ME, Lowe ED, Hunt JF, Montelione GT, Tong L, Snell EH, Garman EF. High-Throughput PIXE as an Essential Quantitative Assay for Accurate Metalloprotein Structural Analysis: Development and Application. J Am Chem Soc 2019; 142:185-197. [PMID: 31794207 DOI: 10.1021/jacs.9b09186] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Metalloproteins comprise over one-third of proteins, with approximately half of all enzymes requiring metal to function. Accurate identification of these metal atoms and their environment is a prerequisite to understanding biological mechanism. Using ion beam analysis through particle induced X-ray emission (PIXE), we have quantitatively identified the metal atoms in 30 previously structurally characterized proteins using minimal sample volume and a high-throughput approach. Over half of these metals had been misidentified in the deposited structural models. Some of the PIXE detected metals not seen in the models were explainable as artifacts from promiscuous crystallization reagents. For others, using the correct metal improved the structural models. For multinuclear sites, anomalous diffraction signals enabled the positioning of the correct metals to reveal previously obscured biological information. PIXE is insensitive to the chemical environment, but coupled with experimental diffraction data deposited alongside the structural model it enables validation and potential remediation of metalloprotein models, improving structural and, more importantly, mechanistic knowledge.
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Affiliation(s)
- Geoffrey W Grime
- Ion Beam Centre, Advanced Technology Institute , University of Surrey , Guildford, Surrey GU2 7XH , United Kingdom
| | - Oliver B Zeldin
- Department of Biochemistry , University of Oxford , South Parks Road , Oxford OX1 3QU , United Kingdom
| | - Mary E Snell
- Hauptman-Woodward Medical Research Institute , 700 Ellicott St. , Buffalo , New York 14203 , United States
| | - Edward D Lowe
- Department of Biochemistry , University of Oxford , South Parks Road , Oxford OX1 3QU , United Kingdom
| | - John F Hunt
- Department of Biological Sciences , Columbia University , New York , New York 10027 , United States
| | - Gaetano T Montelione
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Sciences , Rensselaer Polytechnic Institute , Troy New York 12180 United States
| | - Liang Tong
- Department of Biological Sciences , Columbia University , New York , New York 10027 , United States
| | - Edward H Snell
- Hauptman-Woodward Medical Research Institute , 700 Ellicott St. , Buffalo , New York 14203 , United States.,Materials Design and Innovation , SUNY Buffalo , 700 Ellicott St. , Buffalo , New York 14203 , United States
| | - Elspeth F Garman
- Department of Biochemistry , University of Oxford , South Parks Road , Oxford OX1 3QU , United Kingdom
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10
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Wang X, Jing X, Deng Y, Nie Y, Xu F, Xu Y, Zhao YL, Hunt JF, Montelione GT, Szyperski T. Evolutionary coupling saturation mutagenesis: Coevolution-guided identification of distant sites influencing Bacillus naganoensis pullulanase activity. FEBS Lett 2019; 594:799-812. [PMID: 31665817 DOI: 10.1002/1873-3468.13652] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/15/2019] [Accepted: 10/25/2019] [Indexed: 01/20/2023]
Abstract
Pullulanases are well-known debranching enzymes hydrolyzing α-1,6-glycosidic linkages. To date, engineering of pullulanase is mainly focused on catalytic pocket or domain tailoring based on structure/sequence information. Saturation mutagenesis-involved directed evolution is, however, limited by the low number of mutational sites compatible with combinatorial libraries of feasible size. Using Bacillus naganoensis pullulanase as a target protein, here we introduce the 'evolutionary coupling saturation mutagenesis' (ECSM) approach: residue pair covariances are calculated to identify residues for saturation mutagenesis, focusing directed evolution on residue pairs playing important roles in natural evolution. Evolutionary coupling (EC) analysis identified seven residue pairs as evolutionary mutational hotspots. Subsequent saturation mutagenesis yielded variants with enhanced catalytic activity. The functional pairs apparently represent distant sites affecting enzyme activity.
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Affiliation(s)
- Xinye Wang
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Xiaoran Jing
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Yi Deng
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Yao Nie
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Fei Xu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Yan Xu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Yi-Lei Zhao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, MOE-LSB & MOE-LSC, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, China
| | - John F Hunt
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Gaetano T Montelione
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.,Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.,Department of Chemistry and Chemical Biology, and Center for Biotechnology and Integrative Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Thomas Szyperski
- Department of Chemistry, The State University of New York at Buffalo, NY, USA
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11
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Ousalem F, Singh S, Chesneau O, Hunt JF, Boël G. ABC-F proteins in mRNA translation and antibiotic resistance. Res Microbiol 2019; 170:435-447. [PMID: 31563533 DOI: 10.1016/j.resmic.2019.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/01/2019] [Accepted: 09/11/2019] [Indexed: 12/15/2022]
Abstract
The ATP binding cassette protein superfamily comprises ATPase enzymes which are, for the most part, involved in transmembrane transport. Within this superfamily however, some protein families have other functions unrelated to transport. One example is the ABC-F family, which comprises an extremely diverse set of cytoplasmic proteins. All of the proteins in the ABC-F family characterized to date act on the ribosome and are translation factors. Their common function is ATP-dependent modulation of the stereochemistry of the peptidyl transferase center (PTC) in the ribosome coupled to changes in its global conformation and P-site tRNA binding geometry. In this review, we give an overview of the function, structure, and theories for the mechanisms-of-action of microbial proteins in the ABC-F family, including those involved in mediating resistance to ribosome-binding antibiotics.
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Affiliation(s)
- Farès Ousalem
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, 75005, Paris, France
| | - Shikha Singh
- Department of Biological, 702A Sherman Fairchild Center, Columbia University, New York, NY, 10027, United States
| | - Olivier Chesneau
- Département de Microbiologie, Institut Pasteur, 75724, Paris Cedex 15, France.
| | - John F Hunt
- Department of Biological, 702A Sherman Fairchild Center, Columbia University, New York, NY, 10027, United States.
| | - Grégory Boël
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique, 75005, Paris, France.
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12
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Zhang M, Yu XW, Xu Y, Guo RT, Swapna GVT, Szyperski T, Hunt JF, Montelione GT. Structural Basis by Which the N-Terminal Polypeptide Segment of Rhizopus chinensis Lipase Regulates Its Substrate Binding Affinity. Biochemistry 2019; 58:3943-3954. [PMID: 31436959 PMCID: PMC7195698 DOI: 10.1021/acs.biochem.9b00462] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Members of an important group of industrial enzymes, Rhizopus lipases, exhibit valuable hydrolytic features that underlie their biological functions. Particularly important is their N-terminal polypeptide segment (NTPS), which is required for secretion and proper folding but is removed in the process of enzyme maturation. A second common feature of this class of lipases is the α-helical "lid", which regulates the accessibility of the substrate to the enzyme active site. Some Rhizopus lipases also exhibit "interfacial activation" by micelle and/or aggregate surfaces. While it has long been recognized that the NTPS is critical for function, its dynamic features have frustrated efforts to characterize its structure by X-ray crystallography. Here, we combine nuclear magnetic resonance spectroscopy and X-ray crystallography to determine the structure and dynamics of Rhizopus chinensis lipase (RCL) with its 27-residue NTPS prosequence (r27RCL). Both r27RCL and the truncated mature form of RCL (mRCL) exhibit biphasic interfacial activation kinetics with p-nitrophenyl butyrate (pNPB). r27RCL exhibits a substrate binding affinity significantly lower than that of mRCL due to stabilization of the closed lid conformation by the NTPS. In contrast to previous predictions, the NTPS does not enhance lipase activity by increasing surface hydrophobicity but rather inhibits activity by forming conserved interactions with both the closed lid and the core protein structure. Single-site mutations and kinetic studies were used to confirm that the NTPS serves as internal competitive inhibitor and to develop a model of the associated process of interfacial activation. These structure-function studies provide the basis for engineering RCL lipases with enhanced catalytic activities.
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Affiliation(s)
- Meng Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, People’s Republic of China
| | - Xiao-Wei Yu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, People’s Republic of China
| | - Yan Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, People’s Republic of China
| | - Rey-Ting Guo
- Industrial Enzyme National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, People’s Republic of China
| | - G. V. T. Swapna
- Center for Advanced Biotechnology and Medicine, and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Thomas Szyperski
- Department of Chemistry, State University of New York at Buffalo, Buffalo, New York, 14260. USA
| | - John F. Hunt
- Department of Biological Science, Columbia University, New York, New York 10027, USA
| | - Gaetano T. Montelione
- Center for Advanced Biotechnology and Medicine, and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854, USA
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854, USA
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13
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Abstract
Synonymous variations in protein-coding sequences alter protein expression dynamics, which has important implications for cellular physiology and evolutionary fitness, but disentangling the underlying molecular mechanisms remains challenging.
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Affiliation(s)
| | - Gregory Boël
- Institut de Biologie Physico-Chemique, CNRS, 75005 Paris, France.
| | - John F Hunt
- Department of Biological Sciences, Columbia University, New York, NY 10024, USA.
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14
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Lipońska A, Ousalem F, Aalberts DP, Hunt JF, Boël G. The new strategies to overcome challenges in protein production in bacteria. Microb Biotechnol 2019; 12:44-47. [PMID: 30484965 PMCID: PMC6302713 DOI: 10.1111/1751-7915.13338] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 12/13/2022] Open
Abstract
Recombinant proteins are essential for biotechnology. Here we review some of the key points for improving the production of heterologous proteins, and what can be the future of the field.
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Affiliation(s)
- Anna Lipońska
- Institut de Biologie Physico‐ChimiqueSorbonne Paris CitéUMR 8261 CNRS‐University Paris Diderot13 rue Pierre et Marie Curie75005ParisFrance
| | - Farès Ousalem
- Institut de Biologie Physico‐ChimiqueSorbonne Paris CitéUMR 8261 CNRS‐University Paris Diderot13 rue Pierre et Marie Curie75005ParisFrance
| | | | - John F. Hunt
- Department of Biological SciencesColumbia UniversityNew YorkNY10027USA
| | - Grégory Boël
- Institut de Biologie Physico‐ChimiqueSorbonne Paris CitéUMR 8261 CNRS‐University Paris Diderot13 rue Pierre et Marie Curie75005ParisFrance
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15
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Wang C, Aleksandrov AA, Yang Z, Forouhar F, Proctor EA, Kota P, An J, Kaplan A, Khazanov N, Boël G, Stockwell BR, Senderowitz H, Dokholyan NV, Riordan JR, Brouillette CG, Hunt JF. Ligand binding to a remote site thermodynamically corrects the F508del mutation in the human cystic fibrosis transmembrane conductance regulator. J Biol Chem 2018; 293:17685-17704. [PMID: 29903914 PMCID: PMC6240863 DOI: 10.1074/jbc.ra117.000819] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 05/31/2018] [Indexed: 01/07/2023] Open
Abstract
Many disease-causing mutations impair protein stability. Here, we explore a thermodynamic strategy to correct the disease-causing F508del mutation in the human cystic fibrosis transmembrane conductance regulator (hCFTR). F508del destabilizes nucleotide-binding domain 1 (hNBD1) in hCFTR relative to an aggregation-prone intermediate. We developed a fluorescence self-quenching assay for compounds that prevent aggregation of hNBD1 by stabilizing its native conformation. Unexpectedly, we found that dTTP and nucleotide analogs with exocyclic methyl groups bind to hNBD1 more strongly than ATP and preserve electrophysiological function of full-length F508del-hCFTR channels at temperatures up to 37 °C. Furthermore, nucleotides that increase open-channel probability, which reflects stabilization of an interdomain interface to hNBD1, thermally protect full-length F508del-hCFTR even when they do not stabilize isolated hNBD1. Therefore, stabilization of hNBD1 itself or of one of its interdomain interfaces by a small molecule indirectly offsets the destabilizing effect of the F508del mutation on full-length hCFTR. These results indicate that high-affinity binding of a small molecule to a remote site can correct a disease-causing mutation. We propose that the strategies described here should be applicable to identifying small molecules to help manage other human diseases caused by mutations that destabilize native protein conformation.
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Affiliation(s)
- Chi Wang
- From the Departments of Biological Sciences and
| | - Andrei A. Aleksandrov
- the Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Zhengrong Yang
- the Department of Chemistry, University of Alabama, Birmingham, Alabama 35294, and
| | | | - Elizabeth A. Proctor
- the Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Pradeep Kota
- the Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Jianli An
- the Department of Chemistry, University of Alabama, Birmingham, Alabama 35294, and
| | - Anna Kaplan
- From the Departments of Biological Sciences and
| | - Netaly Khazanov
- the Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | | | - Brent R. Stockwell
- From the Departments of Biological Sciences and ,Chemistry, Columbia University, New York, New York 10027
| | - Hanoch Senderowitz
- the Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Nikolay V. Dokholyan
- the Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - John R. Riordan
- the Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | | | - John F. Hunt
- From the Departments of Biological Sciences and , To whom correspondence should be addressed. Tel.:
212-854-5443; Fax:
212-865-8246; E-mail:
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16
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Nie Y, Wang S, Xu Y, Luo S, Zhao YL, Xiao R, Montelione GT, Hunt JF, Szyperski T. Enzyme Engineering Based on X-ray Structures and Kinetic Profiling of Substrate Libraries: Alcohol Dehydrogenases for Stereospecific Synthesis of a Broad Range of Chiral Alcohols. ACS Catal 2018. [DOI: 10.1021/acscatal.8b00364] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Yao Nie
- School of Biotechnology, Key laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, People’s Republic of China
| | - Shanshan Wang
- School of Biotechnology, Key laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, People’s Republic of China
- School of Biological Science and Engineering, Shannxi University of Technology, Hanzhong 723001, People’s Republic of China
| | - Yan Xu
- School of Biotechnology, Key laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, People’s Republic of China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, People’s Republic of China
| | - Shenggan Luo
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, MOE-LSB & MOE-LSC, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Yi-Lei Zhao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, MOE-LSB & MOE-LSC, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Rong Xiao
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Gaetano T. Montelione
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - John F. Hunt
- Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Thomas Szyperski
- Department of Chemistry, The State University of New York at Buffalo, Buffalo, New York 14260, United States
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17
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Thomas RG, Rivera Reyes BM, Gaston BM, Rivera Acosta NB, Bederman IR, Smith LA, Sutton MT, Wang B, Hunt JF, Bonfield TL. Conjugation of nitrated acetaminophen to Der p1 amplifies peripheral blood monocyte response to Der p1. PLoS One 2017; 12:e0188614. [PMID: 29228007 PMCID: PMC5724819 DOI: 10.1371/journal.pone.0188614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/12/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND An association of acetaminophen use and asthma was observed in the International Study of Asthma and Allergies in Childhood study. However there are no clear mechanisms to explain an association between acetaminophen use and immunologic pathology. In acidic conditions like those in the stomach and inflamed airway, tyrosine residues are nitrated by nitrous and peroxynitrous acids. The resulting nitrotyrosine is structurally similar to 2,4-dinitrophenol and 2,4-dinitrochlorobenzene, known haptens that enhance immune responses by covalently binding proteins. Nitrated acetaminophen shares similar molecular structure. OBJECTIVE We hypothesized the acetaminophen phenol ring undergoes nitration under acidic conditions, producing 3-nitro-acetaminophen which augments allergic responses by acting as a hapten for environmental allergens. METHODS 3-nitro-acetaminophen was formed from acetaminophen in the presence of acidified nitrite, purified by high performance liquid chromatography, and assayed by gas-chromatography mass spectrometry. Purified 3-nitro-acetaminophen was reacted with Dermatophagoides pteronyssinus (Der p1) and analyzed by mass spectrometry to identify the modification site. Human peripheral blood mononuclear cells proliferation response was measured in response to 3-nitro-acetaminophen and to 3-nitro-acetaminophen-modified Der p1. RESULTS Acetaminophen was modified by nitrous acid forming 3-nitro-acetaminophen over a range of different acidic conditions consistent with airway inflammation and stomach acidity. The Der p1 protein-hapten adduct creation was confirmed by liquid chromatography-mass spectrometry proteomics modifying cysteine 132. Peripheral blood mononuclear cells exposed to 3-nitro-acetaminophen-modified Der p1 had increased proliferation and cytokine production compared to acetaminophen and Der p1 alone (n = 7; p < 0.05). CONCLUSION These data suggests 3-nitro-acetaminophen formation and reaction with Der p1 provides a mechanism by which stomach acid or infection-induced low airway pH in patients could enhance the allergic response to proteins such as Der p1.
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Affiliation(s)
- Ryan G. Thomas
- Department of Pediatrics, Division of Pulmonology, University Hospitals Cleveland Medical Center, Rainbow Babies and Children’s Hospital, Cleveland, Ohio, United States of America
- Department of Pediatrics, Division of Pulmonology, Case Western Reserve University, Cleveland, United States of America
| | - Brenda M. Rivera Reyes
- Department of Pediatrics, Division of Pulmonology, University Hospitals Cleveland Medical Center, Rainbow Babies and Children’s Hospital, Cleveland, Ohio, United States of America
- Department of Pediatrics, Division of Pulmonology, Case Western Reserve University, Cleveland, United States of America
| | - Benjamin M. Gaston
- Department of Pediatrics, Division of Pulmonology, University Hospitals Cleveland Medical Center, Rainbow Babies and Children’s Hospital, Cleveland, Ohio, United States of America
- Department of Pediatrics, Division of Pulmonology, Case Western Reserve University, Cleveland, United States of America
| | - Nelki B. Rivera Acosta
- Department of Pediatrics, Division of Pulmonology, University Hospitals Cleveland Medical Center, Rainbow Babies and Children’s Hospital, Cleveland, Ohio, United States of America
| | - Ilya R. Bederman
- Department of Pediatrics, Division of Pulmonology, Case Western Reserve University, Cleveland, United States of America
| | - Laura A. Smith
- Department of Pediatrics, Division of Pulmonology, Case Western Reserve University, Cleveland, United States of America
| | - Morgan T. Sutton
- Department of Pediatrics, Division of Pulmonology, Case Western Reserve University, Cleveland, United States of America
| | - Benlian Wang
- Center of Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - John F. Hunt
- Airbase Therapeutics, Charlottesville, Virginia, United States of America
| | - Tracey L. Bonfield
- Department of Pediatrics, Division of Pulmonology, Case Western Reserve University, Cleveland, United States of America
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18
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Zhang M, Yu XW, Xu Y, Jouhten P, Swapna GVT, Glaser RW, Hunt JF, Montelione GT, Maaheimo H, Szyperski T. 13 C metabolic flux profiling of Pichia pastoris grown in aerobic batch cultures on glucose revealed high relative anabolic use of TCA cycle and limited incorporation of provided precursors of branched-chain amino acids. FEBS J 2017; 284:3100-3113. [PMID: 28731268 DOI: 10.1111/febs.14180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/18/2017] [Accepted: 07/18/2017] [Indexed: 01/02/2023]
Abstract
Carbon metabolism of Crabtree-negative yeast Pichia pastoris was profiled using 13 C nuclear magnetic resonance (NMR) to delineate regulation during exponential growth and to study the import of two precursors for branched-chain amino acid biosynthesis, α-ketoisovalerate and α-ketobutyrate. Cells were grown in aerobic batch cultures containing (a) only glucose, (b) glucose along with the precursors, or (c) glucose and Val. The study provided the following new insights. First, 13 C flux ratio analyses of central metabolism reveal an unexpectedly high anaplerotic supply of the tricarboxylic acid cycle for a Crabtree-negative yeast, and show that a substantial fraction of glucose catabolism proceeds through the pentose phosphate pathway. A comparison with previous flux ratio analyses for batch cultures of Crabtree-negative Pichia stipitis and Crabtree-positive Saccharomyces cerevisiae indicate that the overall regulation of central carbon metabolism in P. pastoris is intermediate in between P. stipitis and S. cerevisiae. Second, excess α-ketoisovalerate in the medium is not transported into the cytoplasm indicating that P. pastoris lacks a suitable transporter. In contrast, excess Val is efficiently taken up and largely fulfills demands for both Val and Leu for protein synthesis. Third, excess α-ketobutyrate is transported into the mitochondria for Ile biosynthesis. However, the import does not efficiently inhibit the synthesis of α-ketobutyrate from pyruvate indicating that P. pastoris has not been optimized evolutionarily to take full advantage of this carbon source. These findings have direct implications for preparing uniformly 2 H,13 C,15 N-labeled proteins containing protonated Ile, Val, and Leu methyl groups in P. pastoris for NMR-based structural biology. ENZYMES Acetohydroxy acid isomeroreductase (EC 1.1.1.86), branched-chain amino acid aminotransferase (BCAT, EC 2.6.1.42), fumarase (EC 4.2.1.2), malic enzyme (EC 1.1.1.39/1.1.1.40), phosphoenolpyruvate carboxykinase (EC 4.1.1.49), pyruvate carboxylase (EC 6.4.1.1), pyruvate kinase (EC 2.7.1.40), l-serine hydroxymethyltransferase (EC 2.1.2.1), threonine aldolase (EC 4.1.2.5), threonine dehydratase (EC 4.3.1.19); transketolase (EC 2.2.1.1), transaldolase (EC 2.2.1.2).
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Affiliation(s)
- Meng Zhang
- School of Biotechnology, Key Laboratory of Industrial Biotechnology, State Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Xiao-Wei Yu
- School of Biotechnology, Key Laboratory of Industrial Biotechnology, State Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Yan Xu
- School of Biotechnology, Key Laboratory of Industrial Biotechnology, State Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, Wuxi, China
| | - Paula Jouhten
- European Molecular Biology Laboratory Heidelberg, Germany
| | - Gurla V T Swapna
- Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Ralf W Glaser
- Institute of Biochemistry and Biophysics, Friedrich-Schiller-Universität, Jena, Germany
| | - John F Hunt
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Gaetano T Montelione
- Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.,Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Hannu Maaheimo
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Thomas Szyperski
- Department of Chemistry, State University of New York at Buffalo, NY, USA
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19
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Thiaville JJ, Flood J, Yurgel S, Prunetti L, Elbadawi-Sidhu M, Hutinet G, Forouhar F, Zhang X, Ganesan V, Reddy P, Fiehn O, Gerlt JA, Hunt JF, Copley SD, de Crécy-Lagard V. Members of a Novel Kinase Family (DUF1537) Can Recycle Toxic Intermediates into an Essential Metabolite. ACS Chem Biol 2016; 11:2304-11. [PMID: 27294475 DOI: 10.1021/acschembio.6b00279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
DUF1537 is a novel family of kinases identified by comparative genomic approaches. The family is widespread and found in all sequenced plant genomes and 16% of sequenced bacterial genomes. DUF1537 is not a monofunctional family and contains subgroups that can be separated by phylogenetic and genome neighborhood context analyses. A subset of the DUF1537 proteins is strongly associated by physical clustering and gene fusion with the PdxA2 family, demonstrated here to be a functional paralog of the 4-phosphohydroxy-l-threonine dehydrogenase enzyme (PdxA), a central enzyme in the synthesis of pyridoxal-5'-phosphate (PLP) in proteobacteria. Some members of this DUF1537 subgroup phosphorylate l-4-hydroxythreonine (4HT) into 4-phosphohydroxy-l-threonine (4PHT), the substrate of PdxA, in vitro and in vivo. This provides an alternative route to PLP from the toxic antimetabolite 4HT that can be directly generated from the toxic intermediate glycolaldehyde. Although the kinetic and physical clustering data indicate that these functions in PLP synthesis are not the main roles of the DUF1537-PdxA2 enzymes, genetic and physiological data suggest these side activities function has been maintained in diverse sets of organisms.
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Affiliation(s)
- Jennifer J. Thiaville
- Department
of Microbiology and Cell Science and Genetic Institute, University of Florida, P.O. Box 110700, Gainesville, Florida 32611-0700, United States
| | - Jake Flood
- Department
of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado United States
| | - Svetlana Yurgel
- Dalhousie University, 6299 South
St., Halifax, NS B3H 4R2, Canada
| | - Laurence Prunetti
- Department
of Microbiology and Cell Science and Genetic Institute, University of Florida, P.O. Box 110700, Gainesville, Florida 32611-0700, United States
| | | | - Geoffrey Hutinet
- Department
of Microbiology and Cell Science and Genetic Institute, University of Florida, P.O. Box 110700, Gainesville, Florida 32611-0700, United States
| | - Farhad Forouhar
- Department
of Biological Sciences, Columbia University, New York, New York, United States
| | - Xinshuai Zhang
- Institute
for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Venkateswaran Ganesan
- Department
of Microbiology and Cell Science and Genetic Institute, University of Florida, P.O. Box 110700, Gainesville, Florida 32611-0700, United States
| | - Patrick Reddy
- Department
of Microbiology and Cell Science and Genetic Institute, University of Florida, P.O. Box 110700, Gainesville, Florida 32611-0700, United States
| | - Oliver Fiehn
- West
Coast Metabolomics Center, UC Davis, Davis, California, United States
- King Abdulaziz University, Biochemistry Department, Jeddah, Saudi Arabia
| | - J. A. Gerlt
- Institute
for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - John F. Hunt
- Department
of Biological Sciences, Columbia University, New York, New York, United States
| | - Shelley D. Copley
- Department
of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado United States
| | - Valérie de Crécy-Lagard
- Department
of Microbiology and Cell Science and Genetic Institute, University of Florida, P.O. Box 110700, Gainesville, Florida 32611-0700, United States
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20
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King IC, Gleixner J, Doyle L, Kuzin A, Hunt JF, Xiao R, Montelione GT, Stoddard BL, DiMaio F, Baker D. Precise assembly of complex beta sheet topologies from de novo designed building blocks. eLife 2015; 4. [PMID: 26650357 PMCID: PMC4737653 DOI: 10.7554/elife.11012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/08/2015] [Indexed: 01/22/2023] Open
Abstract
Design of complex alpha-beta protein topologies poses a challenge because of the large number of alternative packing arrangements. A similar challenge presumably limited the emergence of large and complex protein topologies in evolution. Here, we demonstrate that protein topologies with six and seven-stranded beta sheets can be designed by insertion of one de novo designed beta sheet containing protein into another such that the two beta sheets are merged to form a single extended sheet, followed by amino acid sequence optimization at the newly formed strand-strand, strand-helix, and helix-helix interfaces. Crystal structures of two such designs closely match the computational design models. Searches for similar structures in the SCOP protein domain database yield only weak matches with different beta sheet connectivities. A similar beta sheet fusion mechanism may have contributed to the emergence of complex beta sheets during natural protein evolution. DOI:http://dx.doi.org/10.7554/eLife.11012.001 A protein is made up of a sequence of amino acids and must fold into a specific three-dimensional structure if it is to work correctly. The structure is formed by segments of the protein adopting specific shapes, the two most common shapes being alpha helices and beta strands. Beta strands commonly interact with each other to form regions called beta sheets. Researchers trying to design proteins with new abilities have managed to create proteins that contain up to five beta strands and four alpha helices. Larger and more complex proteins are more challenging to make because there are many different ways that a protein can fold. It is also difficult to understand how complex structures such as large beta sheets emerged naturally, over the course of evolution. King et al. have now used computer modeling to explore how a large, complex beta sheet might form. In the model, one small, newly designed protein was inserted into another so that their beta sheets merged to form a single extended sheet. The model then stabilized this structure by changing the amino acids found at the points where the two proteins met. King et al. were then able to synthesize these new proteins in bacteria and use a technique called X-ray crystallography to determine the structure of two of them. The structures closely matched the computer models; one protein contained a six-stranded beta sheet, and the other had a seven-stranded beta sheet. The folds of the two designed proteins were then compared with those found in a database that classifies proteins on the basis of their structure. The beta sheets in the designed proteins did not match the protein structures in the database, which suggests that the designed proteins contained new types of folds. In the future, the technique used by King et al. could be used to design other large and complex beta sheet structures. Furthermore, the results suggest that such large structures could have evolved naturally through the combination of smaller, less complex proteins. DOI:http://dx.doi.org/10.7554/eLife.11012.002
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Affiliation(s)
- Indigo Chris King
- Institute for Protein Design, University of Washington, Seattle, United States
| | - James Gleixner
- Institute for Protein Design, University of Washington, Seattle, United States
| | - Lindsey Doyle
- Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Alexandre Kuzin
- Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, United States
| | - John F Hunt
- Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, United States
| | - Rong Xiao
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, United States
| | - Gaetano T Montelione
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, United States
| | - Barry L Stoddard
- Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Frank DiMaio
- Institute for Protein Design, University of Washington, Seattle, United States
| | - David Baker
- Institute for Protein Design, University of Washington, Seattle, United States
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21
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Everett JK, Tejero R, Murthy SBK, Acton TB, Aramini JM, Baran MC, Benach J, Cort JR, Eletsky A, Forouhar F, Guan R, Kuzin AP, Lee HW, Liu G, Mani R, Mao B, Mills JL, Montelione AF, Pederson K, Powers R, Ramelot T, Rossi P, Seetharaman J, Snyder D, Swapna GVT, Vorobiev SM, Wu Y, Xiao R, Yang Y, Arrowsmith CH, Hunt JF, Kennedy MA, Prestegard JH, Szyperski T, Tong L, Montelione GT. A community resource of experimental data for NMR / X-ray crystal structure pairs. Protein Sci 2015; 25:30-45. [PMID: 26293815 DOI: 10.1002/pro.2774] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/17/2015] [Indexed: 12/11/2022]
Abstract
We have developed an online NMR / X-ray Structure Pair Data Repository. The NIGMS Protein Structure Initiative (PSI) has provided many valuable reagents, 3D structures, and technologies for structural biology. The Northeast Structural Genomics Consortium was one of several PSI centers. NESG used both X-ray crystallography and NMR spectroscopy for protein structure determination. A key goal of the PSI was to provide experimental structures for at least one representative of each of hundreds of targeted protein domain families. In some cases, structures for identical (or nearly identical) constructs were determined by both NMR and X-ray crystallography. NMR spectroscopy and X-ray diffraction data for 41 of these "NMR / X-ray" structure pairs determined using conventional triple-resonance NMR methods with extensive sidechain resonance assignments have been organized in an online NMR / X-ray Structure Pair Data Repository. In addition, several NMR data sets for perdeuterated, methyl-protonated protein samples are included in this repository. As an example of the utility of this repository, these data were used to revisit questions about the precision and accuracy of protein NMR structures first outlined by Levy and coworkers several years ago (Andrec et al., Proteins 2007;69:449-465). These results demonstrate that the agreement between NMR and X-ray crystal structures is improved using modern methods of protein NMR spectroscopy. The NMR / X-ray Structure Pair Data Repository will provide a valuable resource for new computational NMR methods development.
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Affiliation(s)
- John K Everett
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Roberto Tejero
- Departamento De Química Física, Universidad De Valencia, Valencia, Spain
| | - Sarath B K Murthy
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Thomas B Acton
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - James M Aramini
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Michael C Baran
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Jordi Benach
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY, 10027, USA
| | - John R Cort
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, 99354, USA
| | - Alexander Eletsky
- Department of Chemistry, The State University of New York at Buffalo, and Northeast Structural Genomics Consortium, Buffalo, New York, 14260, USA
| | - Farhad Forouhar
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY, 10027, USA
| | - Rongjin Guan
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Alexandre P Kuzin
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY, 10027, USA
| | - Hsiau-Wei Lee
- Complex Carbohydrate Research Center and Northeast Structural Genomics Consortium, University of Georgia, Athens, Georgia, 30602, USA
| | - Gaohua Liu
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Rajeswari Mani
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Binchen Mao
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Jeffrey L Mills
- Department of Chemistry, The State University of New York at Buffalo, and Northeast Structural Genomics Consortium, Buffalo, New York, 14260, USA
| | - Alexander F Montelione
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Kari Pederson
- Complex Carbohydrate Research Center and Northeast Structural Genomics Consortium, University of Georgia, Athens, Georgia, 30602, USA
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588, USA
| | - Theresa Ramelot
- Department of Chemistry and Biochemistry, Northeast Structural Genomics Consortium, Miami University, Oxford, Ohio, 45056, USA
| | - Paolo Rossi
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Jayaraman Seetharaman
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY, 10027, USA
| | - David Snyder
- Department of Chemistry, College of Science and Health, William Paterson University of NJ, Wayne, New Jersey, 07470, USA
| | - G V T Swapna
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Sergey M Vorobiev
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY, 10027, USA
| | - Yibing Wu
- Department of Chemistry, The State University of New York at Buffalo, and Northeast Structural Genomics Consortium, Buffalo, New York, 14260, USA
| | - Rong Xiao
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Yunhuang Yang
- Department of Chemistry and Biochemistry, Northeast Structural Genomics Consortium, Miami University, Oxford, Ohio, 45056, USA
| | - Cheryl H Arrowsmith
- Cancer Genomics & Proteomics, Department of Medical Biophysics, Ontario Cancer Institute, and Northeast Structural Genomics Consortium, University of Toronto, Toronto, Ontario, M5G 1L7, Canada
| | - John F Hunt
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY, 10027, USA
| | - Michael A Kennedy
- Department of Chemistry and Biochemistry, Northeast Structural Genomics Consortium, Miami University, Oxford, Ohio, 45056, USA
| | - James H Prestegard
- Complex Carbohydrate Research Center and Northeast Structural Genomics Consortium, University of Georgia, Athens, Georgia, 30602, USA
| | - Thomas Szyperski
- Department of Chemistry, The State University of New York at Buffalo, and Northeast Structural Genomics Consortium, Buffalo, New York, 14260, USA
| | - Liang Tong
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY, 10027, USA
| | - Gaetano T Montelione
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA.,Department of Biochemistry, Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
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22
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Abstract
Exhaled breath condensate (EBC) pH serves as a surrogate marker of airway lining fluid (ALF) pH and can be used to evaluate airway acidification (AA). AA is known to be present in acute respiratory distress syndrome (ARDS) and can be evaluated via continuous EBC pH measurement during mechanical ventilation. Lung recruitment maneuvers (LRMs) are utilized in the treatment of ARDS, however, their impact on EBC pH has never been explored. Here we described the acute effects of two commonly used LRMs on EBC pH. In a prospective, non-randomized, serial exposure study, 10 intubated pediatric subjects with acute respiratory distress syndrome sequentially underwent: a period of baseline ventilation, sustained inflation (SI) maneuver of 40 cm H2O for 40 s, open lung ventilation, staircase recruitment strategy (SRS) (which involves a systematic ramping of plateau pressures in 5 cm H2O increments, starting at 30 cm H2O), and PEEP titration. Maximum lung recruitment during the SRS is defined as a PaO2 + PaCO2 of >400 mmHg. Following lung recruitment, PEEP titration was conducted from 20 cm H2O in 2 cm H2O decrements until a PaO2 + PaCO2 was <380 and then increased by 2 cm H2O. EBC pH, arterial blood gases, lung mechanics, hemodynamics, and function residual capacity were obtained following each phase of the LRM and observational period. Seven out of 10 patients were able to reach maximum lung recruitment. Baseline EBC pH (6.38 ± 0.37) did not correlate with disease severity defined by PaO2/FiO2 ratio or oxygenation index (OI). Average EBC pH differed between phases and decreased after LRM (p = 0.001). EBC pH is affected by LRMs. EBC acidification following LRMs may represent a washout effect of opening acidic lung units and ventilating them or acute AA resulting from LRM.
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Affiliation(s)
- Brian K Walsh
- Boston Children's Hospital, 300 Longwood Ave, Farley 019, Boston, MA 02115, USA
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23
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Zallot R, Yazdani M, Goyer A, Ziemak MJ, Guan JC, McCarty DR, deCrécy-Lagard V, Gerdes S, Garrett TJ, Benach J, Hunt JF, Shintani DK, Hanson AD. Salvage of the thiamin pyrimidine moiety by plant TenA proteins lacking an active-site cysteine. Biochem J 2014; 463:145-55. [PMID: 25014715 PMCID: PMC6943918 DOI: 10.1042/bj20140522] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The TenA protein family occurs in prokaryotes, plants and fungi; it has two subfamilies, one (TenA_C) having an active-site cysteine, the other (TenA_E) not. TenA_C proteins participate in thiamin salvage by hydrolysing the thiamin breakdown product amino-HMP (4-amino-5-aminomethyl-2-methylpyrimidine) to HMP (4-amino-5-hydroxymethyl-2-methylpyrimidine); the function of TenA_E proteins is unknown. Comparative analysis of prokaryote and plant genomes predicted that (i) TenA_E has a salvage role similar to, but not identical with, that of TenA_C and (ii) that TenA_E and TenA_C also have non-salvage roles since they occur in organisms that cannot make thiamin. Recombinant Arabidopsis and maize TenA_E proteins (At3g16990, GRMZM2G080501) hydrolysed amino-HMP to HMP and, far more actively, hydrolysed the N-formyl derivative of amino-HMP to amino-HMP. Ablating the At3g16990 gene in a line with a null mutation in the HMP biosynthesis gene ThiC prevented its rescue by amino-HMP. Ablating At3g16990 in the wild-type increased sensitivity to paraquat-induced oxidative stress; HMP overcame this increased sensitivity. Furthermore, the expression of TenA_E and ThiC genes in Arabidopsis and maize was inversely correlated. These results indicate that TenA_E proteins mediate amidohydrolase and aminohydrolase steps in the salvage of thiamin breakdown products. As such products can be toxic, TenA_E proteins may also pre-empt toxicity.
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Affiliation(s)
- Rémi Zallot
- Microbiology and Cell Science Department, University of Florida, Gainesville, FL 32611, U.S.A
| | - Mohammad Yazdani
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, U.S.A
| | - Aymeric Goyer
- Department of Botany and Plant Pathology, Oregon State University, Hermiston, OR 97838, U.S.A
| | - Michael J. Ziemak
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, U.S.A
| | - Jiahn-Chou Guan
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, U.S.A
| | - Donald R. McCarty
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, U.S.A
| | - Valérie deCrécy-Lagard
- Microbiology and Cell Science Department, University of Florida, Gainesville, FL 32611, U.S.A
| | - Svetlana Gerdes
- Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL 60439, U.S.A
| | - Timothy J. Garrett
- College of Medicine, University of Florida, Gainesville, FL 32610, U.S.A
| | - Jordi Benach
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, U.S.A
| | - John F. Hunt
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, U.S.A
| | - David. K. Shintani
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, U.S.A
| | - Andrew D. Hanson
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, U.S.A
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24
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Zallot R, Brochier-Armanet C, Gaston KW, Forouhar F, Limbach PA, Hunt JF, de Crécy-Lagard V. Plant, animal, and fungal micronutrient queuosine is salvaged by members of the DUF2419 protein family. ACS Chem Biol 2014; 9:1812-25. [PMID: 24911101 PMCID: PMC4136680 DOI: 10.1021/cb500278k] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
Queuosine (Q) is a modification found
at the wobble position of
tRNAs with GUN anticodons. Although Q is present in most eukaryotes
and bacteria, only bacteria can synthesize Q de novo. Eukaryotes acquire queuine (q), the free base of Q, from diet and/or
microflora, making q an important but under-recognized micronutrient
for plants, animals, and fungi. Eukaryotic type tRNA-guanine transglycosylases
(eTGTs) are composed of a catalytic subunit (QTRT1) and a homologous
accessory subunit (QTRTD1) forming a complex that catalyzes q insertion
into target tRNAs. Phylogenetic analysis of eTGT subunits revealed
a patchy distribution pattern in which gene losses occurred independently
in different clades. Searches for genes co-distributing with eTGT
family members identified DUF2419 as a potential Q salvage protein
family. This prediction was experimentally validated in Schizosaccharomyces
pombe by confirming that Q was present by analyzing tRNAAsp with anticodon GUC purified from wild-type cells and by
showing that Q was absent from strains carrying deletions in the QTRT1
or DUF2419 encoding genes. DUF2419 proteins occur in most Eukarya
with a few possible cases of horizontal gene transfer to bacteria.
The universality of the DUF2419 function was confirmed by complementing
the S. pombe mutant with the Zea mays (maize), human, and Sphaerobacter thermophilus homologues.
The enzymatic function of this family is yet to be determined, but
structural similarity with DNA glycosidases suggests a ribonucleoside
hydrolase activity.
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Affiliation(s)
- Rémi Zallot
- Department
of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, United States
| | - Céline Brochier-Armanet
- Université
Lyon 1, CNRS, UMR5558, Laboratoire de Biométrie et Biologie
Evolutive, Université de Lyon, 69622 Villeurbanne, France
| | - Kirk W. Gaston
- Rieveschl
Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Farhad Forouhar
- Department
of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - Patrick A. Limbach
- Rieveschl
Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - John F. Hunt
- Department
of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - Valérie de Crécy-Lagard
- Department
of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, United States
- University of Florida Genetics Institute, Gainesville, Florida 32611, United States
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25
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Ergel B, Gill ML, Brown L, Yu B, Palmer AG, Hunt JF. Protein dynamics control the progression and efficiency of the catalytic reaction cycle of the Escherichia coli DNA-repair enzyme AlkB. J Biol Chem 2014; 289:29584-601. [PMID: 25043760 DOI: 10.1074/jbc.m114.575647] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A central goal of enzymology is to understand the physicochemical mechanisms that enable proteins to catalyze complex chemical reactions with high efficiency. Recent methodological advances enable the contribution of protein dynamics to enzyme efficiency to be explored more deeply. Here, we utilize enzymological and biophysical studies, including NMR measurements of conformational dynamics, to develop a quantitative mechanistic scheme for the DNA repair enzyme AlkB. Like other iron/2-oxoglutarate-dependent dioxygenases, AlkB employs a two-step mechanism in which oxidation of 2-oxoglutarate generates a highly reactive enzyme-bound oxyferryl intermediate that, in the case of AlkB, slowly hydroxylates an alkylated nucleobase. Our results demonstrate that a microsecond-to-millisecond time scale conformational transition facilitates the proper sequential order of substrate binding to AlkB. Mutations altering the dynamics of this transition allow generation of the oxyferryl intermediate but promote its premature quenching by solvent, which uncouples 2-oxoglutarate turnover from nucleobase oxidation. Therefore, efficient catalysis by AlkB depends upon the dynamics of a specific conformational transition, establishing another paradigm for the control of enzyme function by protein dynamics.
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Affiliation(s)
- Burçe Ergel
- From the Department of Biological Sciences, Columbia University, New York, New York 10027-6601 and
| | - Michelle L Gill
- the Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032-3702
| | - Lewis Brown
- From the Department of Biological Sciences, Columbia University, New York, New York 10027-6601 and
| | - Bomina Yu
- From the Department of Biological Sciences, Columbia University, New York, New York 10027-6601 and
| | - Arthur G Palmer
- the Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032-3702
| | - John F Hunt
- From the Department of Biological Sciences, Columbia University, New York, New York 10027-6601 and
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26
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Bruno AE, Ruby AM, Luft JR, Grant TD, Seetharaman J, Montelione GT, Hunt JF, Snell EH. Comparing chemistry to outcome: the development of a chemical distance metric, coupled with clustering and hierarchal visualization applied to macromolecular crystallography. PLoS One 2014; 9:e100782. [PMID: 24971458 PMCID: PMC4074061 DOI: 10.1371/journal.pone.0100782] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 05/28/2014] [Indexed: 11/18/2022] Open
Abstract
Many bioscience fields employ high-throughput methods to screen multiple biochemical conditions. The analysis of these becomes tedious without a degree of automation. Crystallization, a rate limiting step in biological X-ray crystallography, is one of these fields. Screening of multiple potential crystallization conditions (cocktails) is the most effective method of probing a proteins phase diagram and guiding crystallization but the interpretation of results can be time-consuming. To aid this empirical approach a cocktail distance coefficient was developed to quantitatively compare macromolecule crystallization conditions and outcome. These coefficients were evaluated against an existing similarity metric developed for crystallization, the C6 metric, using both virtual crystallization screens and by comparison of two related 1,536-cocktail high-throughput crystallization screens. Hierarchical clustering was employed to visualize one of these screens and the crystallization results from an exopolyphosphatase-related protein from Bacteroides fragilis, (BfR192) overlaid on this clustering. This demonstrated a strong correlation between certain chemically related clusters and crystal lead conditions. While this analysis was not used to guide the initial crystallization optimization, it led to the re-evaluation of unexplained peaks in the electron density map of the protein and to the insertion and correct placement of sodium, potassium and phosphate atoms in the structure. With these in place, the resulting structure of the putative active site demonstrated features consistent with active sites of other phosphatases which are involved in binding the phosphoryl moieties of nucleotide triphosphates. The new distance coefficient, CDcoeff, appears to be robust in this application, and coupled with hierarchical clustering and the overlay of crystallization outcome, reveals information of biological relevance. While tested with a single example the potential applications related to crystallography appear promising and the distance coefficient, clustering, and hierarchal visualization of results undoubtedly have applications in wider fields.
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Affiliation(s)
- Andrew E. Bruno
- Center for Computational Research, State University of New York (SUNY), Buffalo, New York, United States of America
| | - Amanda M. Ruby
- Center for Computational Research, State University of New York (SUNY), Buffalo, New York, United States of America
| | - Joseph R. Luft
- Hauptman-Woodward Medical Research Institute, Buffalo, New York, United States of America
- SUNY Buffalo Dept. of Structural Biology, Buffalo, New York, United States of America
| | - Thomas D. Grant
- Hauptman-Woodward Medical Research Institute, Buffalo, New York, United States of America
| | - Jayaraman Seetharaman
- Department of Biological Sciences, The Northeast Structural Genomics Consortium, Columbia University, New York, New York, United States of America
| | - Gaetano T. Montelione
- Northeast Structural Genomics Consortium, Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine and Department of Biochemistry, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - John F. Hunt
- Department of Biological Sciences, The Northeast Structural Genomics Consortium, Columbia University, New York, New York, United States of America
| | - Edward H. Snell
- Hauptman-Woodward Medical Research Institute, Buffalo, New York, United States of America
- SUNY Buffalo Dept. of Structural Biology, Buffalo, New York, United States of America
- * E-mail:
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27
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Yang Z, Wang C, Zhou Q, An J, Hildebrandt E, Aleksandrov LA, Kappes JC, DeLucas LJ, Riordan JR, Urbatsch IL, Hunt JF, Brouillette CG. Membrane protein stability can be compromised by detergent interactions with the extramembranous soluble domains. Protein Sci 2014; 23:769-89. [PMID: 24652590 PMCID: PMC4093953 DOI: 10.1002/pro.2460] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 03/07/2014] [Accepted: 03/17/2014] [Indexed: 11/06/2022]
Abstract
Detergent interaction with extramembranous soluble domains (ESDs) is not commonly considered an important determinant of integral membrane protein (IMP) behavior during purification and crystallization, even though ESDs contribute to the stability of many IMPs. Here we demonstrate that some generally nondenaturing detergents critically destabilize a model ESD, the first nucleotide-binding domain (NBD1) from the human cystic fibrosis transmembrane conductance regulator (CFTR), a model IMP. Notably, the detergents show equivalent trends in their influence on the stability of isolated NBD1 and full-length CFTR. We used differential scanning calorimetry (DSC) and circular dichroism (CD) spectroscopy to monitor changes in NBD1 stability and secondary structure, respectively, during titration with a series of detergents. Their effective harshness in these assays mirrors that widely accepted for their interaction with IMPs, i.e., anionic > zwitterionic > nonionic. It is noteworthy that including lipids or nonionic detergents is shown to mitigate detergent harshness, as will limiting contact time. We infer three thermodynamic mechanisms from the observed thermal destabilization by monomer or micelle: (i) binding to the unfolded state with no change in the native structure (all detergent classes); (ii) native state binding that alters thermodynamic properties and perhaps conformation (nonionic detergents); and (iii) detergent binding that directly leads to denaturation of the native state (anionic and zwitterionic). These results demonstrate that the accepted model for the harshness of detergents applies to their interaction with an ESD. It is concluded that destabilization of extramembranous soluble domains by specific detergents will influence the stability of some IMPs during purification.
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Affiliation(s)
- Zhengrong Yang
- Department of Chemistry, University of Alabama at BirminghamBirmingham, Alabama
- Center for Structural Biology, University of Alabama at BirminghamBirmingham, Alabama
| | - Chi Wang
- Department of Biological Sciences, Columbia UniversityNew York, New York
| | - Qingxian Zhou
- Center for Structural Biology, University of Alabama at BirminghamBirmingham, Alabama
| | - Jianli An
- Center for Structural Biology, University of Alabama at BirminghamBirmingham, Alabama
| | - Ellen Hildebrandt
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, Texas
| | - Luba A Aleksandrov
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel HillChapel Hill, North Carolina
- Cystic Fibrosis Treatment and Research Center, The University of North Carolina at Chapel HillChapel Hill, North Carolina
| | - John C Kappes
- Department of Medicine, University of Alabama at BirminghamBirmingham, Alabama
- Birmingham Veterans Affairs Medical Center, Research ServiceBirmingham, Alabama
| | - Lawrence J DeLucas
- Center for Structural Biology, University of Alabama at BirminghamBirmingham, Alabama
- Department of Optometry, University of Alabama at BirminghamBirmingham, Alabama
| | - John R Riordan
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel HillChapel Hill, North Carolina
- Cystic Fibrosis Treatment and Research Center, The University of North Carolina at Chapel HillChapel Hill, North Carolina
| | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, Texas
- Center for Membrane Protein Research, Texas Tech University Health Sciences CenterLubbock, TX
| | - John F Hunt
- Department of Biological Sciences, Columbia UniversityNew York, New York
| | - Christie G Brouillette
- Department of Chemistry, University of Alabama at BirminghamBirmingham, Alabama
- Center for Structural Biology, University of Alabama at BirminghamBirmingham, Alabama
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28
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Chen B, Boël G, Hashem Y, Ning W, Fei J, Wang C, Gonzalez RL, Hunt JF, Frank J. EttA regulates translation by binding the ribosomal E site and restricting ribosome-tRNA dynamics. Nat Struct Mol Biol 2014; 21:152-9. [PMID: 24389465 PMCID: PMC4143144 DOI: 10.1038/nsmb.2741] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 11/21/2013] [Indexed: 01/12/2023]
Abstract
Cells express many ribosome-interacting factors whose functions and molecular mechanisms remain unknown. Here, we elucidate the mechanism of a newly characterized regulatory translation factor, Energy-dependent Translational Throttle A (EttA), which is an Escherichia coli representative of the ATP-binding cassette F (ABC-F) protein family. Using cryo-EM, we demonstrate that the ATP-bound form of EttA binds to the ribosomal tRNA exit (E) site, where it forms bridging interactions between the ribosomal L1 stalk and the tRNA bound in the peptidyl-tRNA binding (P) site. Using single-molecule fluorescence resonance energy transfer (smFRET), we show that the ATP-bound form of EttA restricts ribosome and tRNA dynamics required for protein synthesis. This work represents the first example, to our knowledge, where the detailed molecular mechanism of any ABC-F family protein has been determined and establishes a framework for elucidating the mechanisms of other regulatory translation factors.
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Affiliation(s)
- Bo Chen
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Grégory Boël
- 1] Department of Biological Sciences, Columbia University, New York, New York, USA. [2] Northeast Structural Genomics Consortium, Columbia University, New York, New York, USA. [3]
| | - Yaser Hashem
- 1] Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA. [2]
| | - Wei Ning
- Department of Chemistry, Columbia University, New York, New York, USA
| | - Jingyi Fei
- 1] Department of Chemistry, Columbia University, New York, New York, USA. [2]
| | - Chi Wang
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Ruben L Gonzalez
- Department of Chemistry, Columbia University, New York, New York, USA
| | - John F Hunt
- 1] Department of Biological Sciences, Columbia University, New York, New York, USA. [2] Northeast Structural Genomics Consortium, Columbia University, New York, New York, USA
| | - Joachim Frank
- 1] Department of Biological Sciences, Columbia University, New York, New York, USA. [2] Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA
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29
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Kronfel CM, Kuzin AP, Forouhar F, Biswas A, Su M, Lew S, Seetharaman J, Xiao R, Everett JK, Ma LC, Acton TB, Montelione GT, Hunt JF, Paul CEC, Dragomani TM, Boutaghou MN, Cole RB, Riml C, Alvey RM, Bryant DA, Schluchter WM. Structural and biochemical characterization of the bilin lyase CpcS from Thermosynechococcus elongatus. Biochemistry 2013; 52:8663-76. [PMID: 24215428 DOI: 10.1021/bi401192z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyanobacterial phycobiliproteins have evolved to capture light energy over most of the visible spectrum due to their bilin chromophores, which are linear tetrapyrroles that have been covalently attached by enzymes called bilin lyases. We report here the crystal structure of a bilin lyase of the CpcS family from Thermosynechococcus elongatus (TeCpcS-III). TeCpcS-III is a 10-stranded β barrel with two alpha helices and belongs to the lipocalin structural family. TeCpcS-III catalyzes both cognate as well as noncognate bilin attachment to a variety of phycobiliprotein subunits. TeCpcS-III ligates phycocyanobilin, phycoerythrobilin, and phytochromobilin to the alpha and beta subunits of allophycocyanin and to the beta subunit of phycocyanin at the Cys82-equivalent position in all cases. The active form of TeCpcS-III is a dimer, which is consistent with the structure observed in the crystal. With the use of the UnaG protein and its association with bilirubin as a guide, a model for the association between the native substrate, phycocyanobilin, and TeCpcS was produced.
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Affiliation(s)
- Christina M Kronfel
- Department of Biological Sciences, University of New Orleans , New Orleans, LA 70148, United States
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30
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Bjelic S, Kipnis Y, Wang L, Pianowski Z, Vorobiev S, Su M, Seetharaman J, Xiao R, Kornhaber G, Hunt JF, Tong L, Hilvert D, Baker D. Exploration of alternate catalytic mechanisms and optimization strategies for retroaldolase design. J Mol Biol 2013; 426:256-71. [PMID: 24161950 DOI: 10.1016/j.jmb.2013.10.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 10/08/2013] [Accepted: 10/09/2013] [Indexed: 12/13/2022]
Abstract
Designed retroaldolases have utilized a nucleophilic lysine to promote carbon-carbon bond cleavage of β-hydroxy-ketones via a covalent Schiff base intermediate. Previous computational designs have incorporated a water molecule to facilitate formation and breakdown of the carbinolamine intermediate to give the Schiff base and to function as a general acid/base. Here we investigate an alternative active-site design in which the catalytic water molecule was replaced by the side chain of a glutamic acid. Five out of seven designs expressed solubly and exhibited catalytic efficiencies similar to previously designed retroaldolases for the conversion of 4-hydroxy-4-(6-methoxy-2-naphthyl)-2-butanone to 6-methoxy-2-naphthaldehyde and acetone. After one round of site-directed saturation mutagenesis, improved variants of the two best designs, RA114 and RA117, exhibited among the highest kcat (>10(-3)s(-1)) and kcat/KM (11-25M(-1)s(-1)) values observed for retroaldolase designs prior to comprehensive directed evolution. In both cases, the >10(5)-fold rate accelerations that were achieved are within 1-3 orders of magnitude of the rate enhancements reported for the best catalysts for related reactions, including catalytic antibodies (kcat/kuncat=10(6) to 10(8)) and an extensively evolved computational design (kcat/kuncat>10(7)). The catalytic sites, revealed by X-ray structures of optimized versions of the two active designs, are in close agreement with the design models except for the catalytic lysine in RA114. We further improved the variants by computational remodeling of the loops and yeast display selection for reactivity of the catalytic lysine with a diketone probe, obtaining an additional order of magnitude enhancement in activity with both approaches.
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Affiliation(s)
- Sinisa Bjelic
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Yakov Kipnis
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Ling Wang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | | | - Sergey Vorobiev
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, USA
| | - Min Su
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, USA
| | - Jayaraman Seetharaman
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, USA
| | - Rong Xiao
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, NJ 08854, USA
| | - Gregory Kornhaber
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, NJ 08854, USA; Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, NJ 08854, USA; Northeast Structural Genomics Consortium, 679 Hoes Lane, Piscataway, NJ 08854, USA
| | - John F Hunt
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, USA
| | - Liang Tong
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, USA
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
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31
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Uemura Y, Nakagawa N, Wakamatsu T, Kim K, Montelione GT, Hunt JF, Kuramitsu S, Masui R. Crystal structure of the ligand-binding form of nanoRNase from Bacteroides fragilis, a member of the DHH/DHHA1 phosphoesterase family of proteins. FEBS Lett 2013; 587:2669-74. [PMID: 23851074 PMCID: PMC4113422 DOI: 10.1016/j.febslet.2013.06.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/25/2013] [Accepted: 07/01/2013] [Indexed: 01/07/2023]
Abstract
NanoRNase (Nrn) specifically degrades nucleoside 3',5'-bisphosphate and the very short RNA, nanoRNA, during the final step of mRNA degradation. The crystal structure of Nrn in complex with a reaction product GMP was determined. The overall structure consists of two domains that are interconnected by a flexible loop and form a cleft. Two Mn²⁺ ions are coordinated by conserved residues in the DHH motif of the N-terminal domain. GMP binds near the DHHA1 motif region in the C-terminal domain. Our structure enables us to predict the substrate-bound form of Nrn as well as other DHH/DHHA1 phosphoesterase family proteins.
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Affiliation(s)
- Yuri Uemura
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Noriko Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan,RIKEN SPring-8 Center, Japan
| | - Taisuke Wakamatsu
- Microbial Genetic Division, Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Kwang Kim
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Gaetano T. Montelione
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - John F. Hunt
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - Seiki Kuramitsu
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan,Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan,RIKEN SPring-8 Center, Japan
| | - Ryoji Masui
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan,RIKEN SPring-8 Center, Japan,Corresponding author: Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1, Machikaneyama-cho, Toyonaka, Osaka 56-0043, Japan. Telephone: +81-6-6850-5434. Fax: +81-6-6850-5442. (R. Masui)
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32
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Procko E, Hedman R, Hamilton K, Seetharaman J, Fleishman SJ, Su M, Aramini J, Kornhaber G, Hunt JF, Tong L, Montelione GT, Baker D. Computational design of a protein-based enzyme inhibitor. J Mol Biol 2013; 425:3563-75. [PMID: 23827138 DOI: 10.1016/j.jmb.2013.06.035] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/15/2013] [Accepted: 06/25/2013] [Indexed: 01/30/2023]
Abstract
While there has been considerable progress in designing protein-protein interactions, the design of proteins that bind polar surfaces is an unmet challenge. We describe the computational design of a protein that binds the acidic active site of hen egg lysozyme and inhibits the enzyme. The design process starts with two polar amino acids that fit deep into the enzyme active site, identifies a protein scaffold that supports these residues and is complementary in shape to the lysozyme active-site region, and finally optimizes the surrounding contact surface for high-affinity binding. Following affinity maturation, a protein designed using this method bound lysozyme with low nanomolar affinity, and a combination of NMR studies, crystallography, and knockout mutagenesis confirmed the designed binding surface and orientation. Saturation mutagenesis with selection and deep sequencing demonstrated that specific designed interactions extending well beyond the centrally grafted polar residues are critical for high-affinity binding.
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Affiliation(s)
- Erik Procko
- Department of Biochemistry and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
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33
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Forouhar F, Arragain S, Atta M, Gambarelli S, Mouesca JM, Hussain M, Xiao R, Kieffer-Jaquinod S, Seetharaman J, Acton TB, Montelione GT, Mulliez E, Hunt JF, Fontecave M. Two Fe-S clusters catalyze sulfur insertion by radical-SAM methylthiotransferases. Nat Chem Biol 2013; 9:333-8. [PMID: 23542644 DOI: 10.1038/nchembio.1229] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 03/05/2013] [Indexed: 11/09/2022]
Abstract
How living organisms create carbon-sulfur bonds during the biosynthesis of critical sulfur-containing compounds is still poorly understood. The methylthiotransferases MiaB and RimO catalyze sulfur insertion into tRNAs and ribosomal protein S12, respectively. Both belong to a subgroup of radical-S-adenosylmethionine (radical-SAM) enzymes that bear two [4Fe-4S] clusters. One cluster binds S-adenosylmethionine and generates an Ado• radical via a well-established mechanism. However, the precise role of the second cluster is unclear. For some sulfur-inserting radical-SAM enzymes, this cluster has been proposed to act as a sacrificial source of sulfur for the reaction. In this paper, we report parallel enzymological, spectroscopic and crystallographic investigations of RimO and MiaB, which provide what is to our knowledge the first evidence that these enzymes are true catalysts and support a new sulfation mechanism involving activation of an exogenous sulfur cosubstrate at an exchangeable coordination site on the second cluster, which remains intact during the reaction.
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Affiliation(s)
- Farhad Forouhar
- Northeast Structural Genomics Consortium, New York, New York, USA
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34
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Kim DM, Zheng H, Huang YJ, Montelione GT, Hunt JF. ATPase active-site electrostatic interactions control the global conformation of the 100 kDa SecA translocase. J Am Chem Soc 2013; 135:2999-3010. [PMID: 23167435 PMCID: PMC4134686 DOI: 10.1021/ja306361q] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
SecA is an intensively studied mechanoenzyme that uses ATP hydrolysis to drive processive extrusion of secreted proteins through a protein-conducting channel in the cytoplasmic membrane of eubacteria. The ATPase motor of SecA is strongly homologous to that in DEAD-box RNA helicases. It remains unclear how local chemical events in its ATPase active site control the overall conformation of an ~100 kDa multidomain enzyme and drive protein transport. In this paper, we use biophysical methods to establish that a single electrostatic charge in the ATPase active site controls the global conformation of SecA. The enzyme undergoes an ATP-modulated endothermic conformational transition (ECT) believed to involve similar structural mechanics to the protein transport reaction. We have characterized the effects of an isosteric glutamate-to-glutamine mutation in the catalytic base, a mutation which mimics the immediate electrostatic consequences of ATP hydrolysis in the active site. Calorimetric studies demonstrate that this mutation facilitates the ECT in Escherichia coli SecA and triggers it completely in Bacillus subtilis SecA. Consistent with the substantial increase in entropy observed in the course of the ECT, hydrogen-deuterium exchange mass spectrometry demonstrates that it increases protein backbone dynamics in domain-domain interfaces at remote locations from the ATPase active site. The catalytic glutamate is one of ~250 charged amino acids in SecA, and yet neutralization of its side chain charge is sufficient to trigger a global order-disorder transition in this 100 kDa enzyme. The intricate network of structural interactions mediating this effect couples local electrostatic changes during ATP hydrolysis to global conformational and dynamic changes in SecA. This network forms the foundation of the allosteric mechanochemistry that efficiently harnesses the chemical energy stored in ATP to drive complex mechanical processes.
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Affiliation(s)
- Dorothy M. Kim
- Department of Biological Sciences and Northeast Structural Genomics Consortium, 702A Fairchild Center, MC2434, Columbia University, New York, NY 10027, USA
- Departments of Biochemistry and Molecular Biophysics, Columbia University, 650 West 168th Street, New York, NY 10032, USA
| | - Haiyan Zheng
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey. Piscataway, New Jersey 08854
| | - Yuanpeng J. Huang
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
| | - Gaetano T. Montelione
- Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, and Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey. Piscataway, New Jersey 08854
| | - John F. Hunt
- Department of Biological Sciences and Northeast Structural Genomics Consortium, 702A Fairchild Center, MC2434, Columbia University, New York, NY 10027, USA
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35
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Abstract
Structural studies of the cystic fibrosis transmembrane conductance regulator (CFTR) are reviewed. Like many membrane proteins, full-length CFTR has proven to be difficult to express and purify, hence much of the structural data available is for the more tractable, independently expressed soluble domains. Therefore, this chapter covers structural data for individual CFTR domains in addition to the sparser data available for the full-length protein. To set the context for these studies, we will start by reviewing structural information on model proteins from the ATP-binding cassette (ABC) transporter superfamily, to which CFTR belongs.
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Affiliation(s)
- John F Hunt
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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36
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Davis MD, Walsh BK, Dwyer ST, Combs C, Vehse N, Paget-Brown A, Pajewski T, Hunt JF. Safety of an alkalinizing buffer designed for inhaled medications in humans. Respir Care 2012; 58:1226-32. [PMID: 23258576 DOI: 10.4187/respcare.01753] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Airway acidification plays a role in disorders of the pulmonary tract. We hypothesized that the inhalation of alkalinized glycine buffer would measurably alkalinize the airways without compromising lung function or causing adverse events. We evaluated the safety of an inhaled alkaline glycine buffer in both healthy subjects and in subjects with stable obstructive airway disease. METHODS This work includes 2 open-label safety studies. The healthy controls were part of a phase 1 safety study of multiple inhalations of low-dose alkaline glycine buffer; nebulized saline was used as a comparator in 8 of the healthy controls. Subsequently, a phase 2 study in subjects with stable obstructive airway disease was completed using a single nebulized higher-dose strategy of the alkaline inhalation. We studied 20 non-smoking adults (10 healthy controls and 10 subjects with obstructive airway disease), both at baseline and after inhalation of alkaline buffer. We used spirometry and vital signs as markers of clinical safety. We used changes in fraction of exhaled nitric oxide (NO) and exhaled breath condensate (EBC) pH as surrogate markers of airway pH modification. RESULTS Alkaline glycine inhalation was tolerated by all subjects in both studies, with no adverse effects on spirometric parameters or vital signs. Airway alkalinization was confirmed by a median increase in EBC pH of 0.235 pH units (IQR 0.56-0.03, P = .03) in subjects after inhalation of the higher-dose alkaline buffer (2.5 mL of 100 mmol/L glycine). CONCLUSIONS Alkalinization of airway lining fluid is accomplished with inhalation of alkaline glycine buffer and causes no adverse effects on pulmonary function or vital signs.
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Affiliation(s)
- Michael D Davis
- Adult Health and Nursing System, Virginia Commonwealth University, Richmond, VA 23298, USA.
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37
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de Crécy-Lagard V, Forouhar F, Brochier-Armanet C, Tong L, Hunt JF. Comparative genomic analysis of the DUF71/COG2102 family predicts roles in diphthamide biosynthesis and B12 salvage. Biol Direct 2012; 7:32. [PMID: 23013770 PMCID: PMC3541065 DOI: 10.1186/1745-6150-7-32] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/18/2012] [Indexed: 01/09/2023] Open
Abstract
Background The availability of over 3000 published genome sequences has enabled the use of comparative genomic approaches to drive the biological function discovery process. Classically, one used to link gene with function by genetic or biochemical approaches, a lengthy process that often took years. Phylogenetic distribution profiles, physical clustering, gene fusion, co-expression profiles, structural information and other genomic or post-genomic derived associations can be now used to make very strong functional hypotheses. Here, we illustrate this shift with the analysis of the DUF71/COG2102 family, a subgroup of the PP-loop ATPase family. Results The DUF71 family contains at least two subfamilies, one of which was predicted to be the missing diphthine-ammonia ligase (EC 6.3.1.14), Dph6. This enzyme catalyzes the last ATP-dependent step in the synthesis of diphthamide, a complex modification of Elongation Factor 2 that can be ADP-ribosylated by bacterial toxins. Dph6 orthologs are found in nearly all sequenced Archaea and Eucarya, as expected from the distribution of the diphthamide modification. The DUF71 family appears to have originated in the Archaea/Eucarya ancestor and to have been subsequently horizontally transferred to Bacteria. Bacterial DUF71 members likely acquired a different function because the diphthamide modification is absent in this Domain of Life. In-depth investigations suggest that some archaeal and bacterial DUF71 proteins participate in B12 salvage. Conclusions This detailed analysis of the DUF71 family members provides an example of the power of integrated data-miming for solving important “missing genes” or “missing function” cases and illustrates the danger of functional annotation of protein families by homology alone. Reviewers’ names This article was reviewed by Arcady Mushegian, Michael Galperin and L. Aravind.
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Affiliation(s)
- Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA.
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38
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Richter F, Blomberg R, Khare SD, Kiss G, Kuzin AP, Smith AJT, Gallaher J, Pianowski Z, Helgeson RC, Grjasnow A, Xiao R, Seetharaman J, Su M, Vorobiev S, Lew S, Forouhar F, Kornhaber GJ, Hunt JF, Montelione GT, Tong L, Houk KN, Hilvert D, Baker D. Computational design of catalytic dyads and oxyanion holes for ester hydrolysis. J Am Chem Soc 2012; 134:16197-206. [PMID: 22871159 DOI: 10.1021/ja3037367] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nucleophilic catalysis is a general strategy for accelerating ester and amide hydrolysis. In natural active sites, nucleophilic elements such as catalytic dyads and triads are usually paired with oxyanion holes for substrate activation, but it is difficult to parse out the independent contributions of these elements or to understand how they emerged in the course of evolution. Here we explore the minimal requirements for esterase activity by computationally designing artificial catalysts using catalytic dyads and oxyanion holes. We found much higher success rates using designed oxyanion holes formed by backbone NH groups rather than by side chains or bridging water molecules and obtained four active designs in different scaffolds by combining this motif with a Cys-His dyad. Following active site optimization, the most active of the variants exhibited a catalytic efficiency (k(cat)/K(M)) of 400 M(-1) s(-1) for the cleavage of a p-nitrophenyl ester. Kinetic experiments indicate that the active site cysteines are rapidly acylated as programmed by design, but the subsequent slow hydrolysis of the acyl-enzyme intermediate limits overall catalytic efficiency. Moreover, the Cys-His dyads are not properly formed in crystal structures of the designed enzymes. These results highlight the challenges that computational design must overcome to achieve high levels of activity.
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Affiliation(s)
- Florian Richter
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
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Ramelot TA, Rossi P, Forouhar F, Lee HW, Yang Y, Ni S, Unser S, Lew S, Seetharaman J, Xiao R, Acton TB, Everett JK, Prestegard JH, Hunt JF, Montelione GT, Kennedy MA. Structure of a specialized acyl carrier protein essential for lipid A biosynthesis with very long-chain fatty acids in open and closed conformations. Biochemistry 2012; 51:7239-49. [PMID: 22876860 DOI: 10.1021/bi300546b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The solution nuclear magnetic resonance (NMR) structures and backbone (15)N dynamics of the specialized acyl carrier protein (ACP), RpAcpXL, from Rhodopseudomonas palustris, in both the apo form and holo form modified by covalent attachment of 4'-phosphopantetheine at S37, are virtually identical, monomeric, and correspond to the closed conformation. The structures have an extra α-helix compared to the archetypical ACP from Escherichia coli, which has four helices, resulting in a larger opening to the hydrophobic cavity. Chemical shift differences between apo- and holo-RpAcpXL indicated some differences in the hinge region between α2 and α3 and in the hydrophobic cavity environment, but corresponding changes in nuclear Overhauser effect cross-peak patterns were not detected. In contrast to the NMR structures, apo-RpAcpXL was observed in an open conformation in crystals that diffracted to 2.0 Å resolution, which resulted from movement of α3. On the basis of the crystal structure, the predicted biological assembly is a homodimer. Although the possible biological significance of dimerization is unknown, there is potential that the resulting large shared hydrophobic cavity could accommodate the very long-chain fatty acid (28-30 carbons) that this specialized ACP is known to synthesize and transfer to lipid A. These structures are the first representatives of the AcpXL family and the first to indicate that dimerization may be important for the function of these specialized ACPs.
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Affiliation(s)
- Theresa A Ramelot
- Department of Chemistry and Biochemistry, Northeast Structural Genomics Consortium, Miami University, Oxford, Ohio 45056, United States.
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Vorobiev SM, Neely H, Yu B, Seetharaman J, Xiao R, Acton TB, Montelione GT, Hunt JF. Crystal structure of a catalytically active GG(D/E)EF diguanylate cyclase domain from Marinobacter aquaeolei with bound c-di-GMP product. ACTA ACUST UNITED AC 2012; 13:177-83. [PMID: 22843345 DOI: 10.1007/s10969-012-9136-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 02/02/2012] [Indexed: 01/06/2023]
Abstract
Recent studies of signal transduction in bacteria have revealed a unique second messenger, bis-(3'-5')-cyclic dimeric GMP (c-di-GMP), which regulates transitions between motile states and sessile states, such as biofilms. C-di-GMP is synthesized from two GTP molecules by diguanylate cyclases (DGC). The catalytic activity of DGCs depends on a conserved GG(D/E)EF domain, usually part of a larger multi-domain protein organization. The domains other than the GG(D/E)EF domain often control DGC activation. This paper presents the 1.83 Å crystal structure of an isolated catalytically competent GG(D/E)EF domain from the A1U3W3_MARAV protein from Marinobacter aquaeolei. Co-crystallization with GTP resulted in enzymatic synthesis of c-di-GMP. Comparison with previously solved DGC structures shows a similar orientation of c-di-GMP bound to an allosteric regulatory site mediating feedback inhibition of the enzyme. Biosynthesis of c-di-GMP in the crystallization reaction establishes that the enzymatic activity of this DGC domain does not require interaction with regulatory domains.
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Affiliation(s)
- Sergey M Vorobiev
- Department of Biological Sciences, The Northeast Structural Genomics Consortium Columbia University, New York, NY, 10032, USA
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Aziz A, Hess JF, Budamagunta MS, Voss JC, Kuzin AP, Huang YJ, Xiao R, Montelione GT, FitzGerald PG, Hunt JF. The structure of vimentin linker 1 and rod 1B domains characterized by site-directed spin-labeling electron paramagnetic resonance (SDSL-EPR) and X-ray crystallography. J Biol Chem 2012; 287:28349-61. [PMID: 22740688 DOI: 10.1074/jbc.m111.334011] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite the passage of ∼30 years since the complete primary sequence of the intermediate filament (IF) protein vimentin was reported, the structure remains unknown for both an individual protomer and the assembled filament. In this report, we present data describing the structure of vimentin linker 1 (L1) and rod 1B. Electron paramagnetic resonance spectra collected from samples bearing site-directed spin labels demonstrate that L1 is not a flexible segment between coiled-coils (CCs) but instead forms a rigid, tightly packed structure. An x-ray crystal structure of a construct containing L1 and rod 1B shows that it forms a tetramer comprising two equivalent parallel CC dimers that interact with one another in the form of a symmetrical anti-parallel dimer. Remarkably, the parallel CC dimers are themselves asymmetrical, which enables them to tetramerize rather than undergoing higher order oligomerization. This functionally vital asymmetry in the CC structure, encoded in the primary sequence of rod 1B, provides a striking example of evolutionary exploitation of the structural plasticity of proteins. EPR and crystallographic data consistently suggest that a very short region within L1 represents a minor local distortion in what is likely to be a continuous CC from the end of rod 1A through the entirety of rod 1B. The concordance of this structural model with previously published cross-linking and spectral data supports the conclusion that the crystallographic oligomer represents a native biological structure.
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Affiliation(s)
- Atya Aziz
- Department of Cell Biology and Human Anatomy, University of California, Davis, California 95616, USA
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Soto-Quiros M, Avila L, Platts-Mills TAE, Hunt JF, Erdman DD, Carper H, Murphy DD, Odio S, James HR, Patrie JT, Hunt W, O'Rourke AK, Davis MD, Steinke JW, Lu X, Kennedy J, Heymann PW. High titers of IgE antibody to dust mite allergen and risk for wheezing among asthmatic children infected with rhinovirus. J Allergy Clin Immunol 2012; 129:1499-1505.e5. [PMID: 22560151 PMCID: PMC3792652 DOI: 10.1016/j.jaci.2012.03.040] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 02/27/2012] [Accepted: 03/27/2012] [Indexed: 01/28/2023]
Abstract
Background The relevance of allergic sensitization, as judged by titers of serum IgE antibodies, to the risk of an asthma exacerbation caused by rhinovirus is unclear. Objective We sought to examine the prevalence of rhinovirus infections in relation to the atopic status of children treated for wheezing in Costa Rica, a country with an increased asthma burden. Methods The children enrolled (n = 287) were 7 through 12 years old. They included 96 with acute wheezing, 65 with stable asthma, and 126 nonasthmatic control subjects. PCR methods, including gene sequencing to identify rhinovirus strains, were used to identify viral pathogens in nasal washes. Results were examined in relation to wheezing, IgE, allergen-specific IgE antibody, and fraction of exhaled nitric oxide levels. Results Sixty-four percent of wheezing children compared with 13% of children with stable asthma and 13% of nonasthmatic control subjects had positive test results for rhinovirus (P < .001 for both comparisons). Among wheezing subjects, 75% of the rhinoviruses detected were group C strains. High titers of IgE antibodies to dust mite allergen (especially Dermatophagoides species) were common and correlated significantly with total IgE and fraction of exhaled nitric oxide levels. The greatest risk for wheezing was observed among children with titers of IgE antibodies to dust mite of 17.5 IU/mL or greater who tested positive for rhinovirus (odds ratio for wheezing, 31.5; 95% CI, 8.3-108; P < .001). Conclusions High titers of IgE antibody to dust mite allergen were common and significantly increased the risk for acute wheezing provoked by rhinovirus among asthmatic children.
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Szefler SJ, Wenzel S, Brown R, Erzurum SC, Fahy JV, Hamilton RG, Hunt JF, Kita H, Liu AH, Panettieri RA, Schleimer RP, Minnicozzi M. Asthma outcomes: biomarkers. J Allergy Clin Immunol 2012; 129:S9-23. [PMID: 22386512 DOI: 10.1016/j.jaci.2011.12.979] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 12/23/2011] [Indexed: 11/25/2022]
Abstract
BACKGROUND Measurement of biomarkers has been incorporated within clinical research studies of asthma to characterize the population and associate the disease with environmental and therapeutic effects. OBJECTIVE National Institutes of Health institutes and federal agencies convened an expert group to propose which biomarkers should be assessed as standardized asthma outcomes in future clinical research studies. METHODS We conducted a comprehensive search of the literature to identify studies that developed and/or tested asthma biomarkers. We identified biomarkers relevant to the underlying disease process progression and response to treatment. We classified the biomarkers as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011. RESULTS Ten measures were identified; only 1, multiallergen screening to define atopy, is recommended as a core asthma outcome. Complete blood counts to measure total eosinophils, fractional exhaled nitric oxide (Feno), sputum eosinophils, urinary leukotrienes, and total and allergen-specific IgE are recommended as supplemental measures. Measurement of sputum polymorphonuclear leukocytes and other analytes, cortisol measures, airway imaging, breath markers, and system-wide studies (eg, genomics, proteomics) are considered as emerging outcome measures. CONCLUSION The working group participants propose the use of multiallergen screening in all asthma clinical trials to characterize study populations with respect to atopic status. Blood, sputum, and urine specimens should be stored in biobanks, and standard procedures should be developed to harmonize sample collection for clinical trial biorepositories.
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Schmier BJ, Seetharaman J, Deutscher MP, Hunt JF, Malhotra A. The structure and enzymatic properties of a novel RNase II family enzyme from Deinococcus radiodurans. J Mol Biol 2012; 415:547-59. [PMID: 22133431 PMCID: PMC3269974 DOI: 10.1016/j.jmb.2011.11.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 11/14/2011] [Accepted: 11/16/2011] [Indexed: 01/07/2023]
Abstract
Exoribonucleases are vital in nearly all aspects of RNA metabolism, including RNA maturation, end-turnover, and degradation. RNase II and RNase R are paralogous members of the RNR superfamily of nonspecific, 3'→5', processive exoribonucleases. In Escherichia coli, RNase II plays a primary role in mRNA decay and has a preference for unstructured RNA. RNase R, in contrast, is capable of digesting structured RNA and plays a role in the degradation of both mRNA and stable RNA. Deinococcus radiodurans, a radiation-resistant bacterium, contains two RNR family members. The shorter of these, DrR63, includes a sequence signature typical of RNase R, but we show here that this enzyme is an RNase II-type exonuclease and cannot degrade structured RNA. We also report the crystal structure of this protein, now termed DrII. The DrII structure reveals a truncated RNA binding region in which the N-terminal cold shock domains, typical of most RNR family nucleases, are replaced by an unusual winged helix-turn-helix domain, where the "wing" is contributed by the C-terminal S1 domain. Consistent with its truncated RNA binding region, DrII is able to remove 3' overhangs from RNA molecules closer to duplexes than do other RNase II-type enzymes. DrII also displays distinct sensitivity to pyrimidine-rich regions of single-stranded RNA and is able to process tRNA precursors with adenosine-rich 3' extensions in vitro. These data indicate that DrII is the RNase II of D. radiodurans and that its structure and catalytic properties are distinct from those of other related enzymes.
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Affiliation(s)
- Brad J. Schmier
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, PO Box 016129, Miami, FL, 33101-6129, USA
| | - Jayaraman Seetharaman
- Northeast Structural Genomics Consortium (NESG) & Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027
| | - Murray P. Deutscher
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, PO Box 016129, Miami, FL, 33101-6129, USA
| | - John F. Hunt
- Northeast Structural Genomics Consortium (NESG) & Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027
| | - Arun Malhotra
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, PO Box 016129, Miami, FL, 33101-6129, USA
- Corresponding Author: Arun Malhotra: Ph: (305) 243-2826; Fax: (305) 243-3955;
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Atta M, Arragain S, Fontecave M, Mulliez E, Hunt JF, Luff JD, Forouhar F. The methylthiolation reaction mediated by the Radical-SAM enzymes. Biochim Biophys Acta 2011; 1824:1223-30. [PMID: 22178611 DOI: 10.1016/j.bbapap.2011.11.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 11/28/2011] [Indexed: 01/29/2023]
Abstract
Over the past 10 years, considerable progress has been made in our understanding of the mechanistic enzymology of the Radical-SAM enzymes. It is now clear that these enzymes appear to be involved in a remarkably wide range of chemically challenging reactions. This review article highlights mechanistic and structural aspects of the methylthiotransferases (MTTases) sub-class of the Radical-SAM enzymes. The mechanism of methylthio insertion, now observed to be performed by three different enzymes is an exciting unsolved problem. This article is part of a Special Issue entitled: Radical SAM enzymes and Radical Enzymology.
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Affiliation(s)
- Mohamed Atta
- Institut de Recherches en Technologie et Sciences pour le Vivant IRTSV-LCBM, UMR 5249 CEA/CNRS/UJF, CEA-Grenoble, 17 avenue des Martyrs, 38054, Grenoble Cedex 09, France.
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Devarakonda S, Gupta K, Chalmers MJ, Hunt JF, Griffin PR, Van Duyne GD, Spiegelman BM. Disorder-to-order transition underlies the structural basis for the assembly of a transcriptionally active PGC-1α/ERRγ complex. Proc Natl Acad Sci U S A 2011; 108:18678-83. [PMID: 22049338 PMCID: PMC3219099 DOI: 10.1073/pnas.1113813108] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Peroxisome proliferator activated receptor (PPAR) γ coactivator-1α (PGC-1α) is a potent transcriptional coactivator of oxidative metabolism and is induced in response to a variety of environmental cues. It regulates a broad array of target genes by coactivating a whole host of transcription factors. The estrogen-related receptor (ERR) family of nuclear receptors are key PGC-1α partners in the regulation of mitochondrial and tissue-specific oxidative metabolic pathways; these receptors also demonstrate strong physical and functional interactions with this coactivator. Here we perform comprehensive biochemical, biophysical, and structural analyses of the complex formed between PGC-1α and ERRγ. PGC-1α activation domain (PGC-1α(2-220)) is intrinsically disordered with limited secondary and no defined tertiary structure. Complex formation with ERRγ induces significant changes in the conformational mobility of both partners, highlighted by significant stabilization of the ligand binding domain (ERRγLBD) as determined by HDX (hydrogen/deuterium exchange) and an observed disorder-to-order transition in PGC-1α(2-220). Small-angle X-ray scattering studies allow for modeling of the solution structure of the activation domain in the absence and presence of ERRγLBD, revealing a stable and compact binary complex. These data show that PGC-1α(2-220) undergoes a large-scale conformational change when binding to the ERRγLBD, leading to substantial compaction of the activation domain. This change results in stable positioning of the N-terminal part of the activation domain of PGC-1α, favorable for assembly of an active transcriptional complex. These data also provide structural insight into the versatile coactivation profile of PGC-1α and can readily be extended to understand other transcriptional coregulators.
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Affiliation(s)
- Srikripa Devarakonda
- Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Kushol Gupta
- Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Michael J. Chalmers
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458; and
| | - John F. Hunt
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
| | - Patrick R. Griffin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458; and
| | - Gregory D. Van Duyne
- Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Bruce M. Spiegelman
- Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA 02115
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Pastore C, Topalidou I, Forouhar F, Yan AC, Levy M, Hunt JF. Crystal structure and RNA binding properties of the RNA recognition motif (RRM) and AlkB domains in human AlkB homolog 8 (ABH8), an enzyme catalyzing tRNA hypermodification. J Biol Chem 2011; 287:2130-43. [PMID: 22065580 DOI: 10.1074/jbc.m111.286187] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Humans express nine paralogs of the bacterial DNA repair enzyme AlkB, an iron/2-oxoglutarate-dependent dioxygenase that reverses alkylation damage to nucleobases. The biochemical and physiological roles of these paralogs remain largely uncharacterized, hampering insight into the evolutionary expansion of the AlkB family. However, AlkB homolog 8 (ABH8), which contains RNA recognition motif (RRM) and methyltransferase domains flanking its AlkB domain, recently was demonstrated to hypermodify the anticodon loops in some tRNAs. To deepen understanding of this activity, we performed physiological and biophysical studies of ABH8. Using GFP fusions, we demonstrate that expression of the Caenorhabditis elegans ABH8 ortholog is widespread in larvae but restricted to a small number of neurons in adults, suggesting that its function becomes more specialized during development. In vitro RNA binding studies on several human ABH8 constructs indicate that binding affinity is enhanced by a basic α-helix at the N terminus of the RRM domain. The 3.0-Å-resolution crystal structure of a construct comprising the RRM and AlkB domains shows disordered loops flanking the active site in the AlkB domain and a unique structural Zn(II)-binding site at its C terminus. Although the catalytic iron center is exposed to solvent, the 2-oxoglutarate co-substrate likely adopts an inactive conformation in the absence of tRNA substrate, which probably inhibits uncoupled free radical generation. A conformational change in the active site coupled to a disorder-to-order transition in the flanking protein segments likely controls ABH8 catalytic activity and tRNA binding specificity. These results provide insight into the functional and structural adaptations underlying evolutionary diversification of AlkB domains.
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Affiliation(s)
- Chiara Pastore
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Kryshtafovych A, Moult J, Bartual SG, Bazan JF, Berman H, Casteel DE, Christodoulou E, Everett JK, Hausmann J, Heidebrecht T, Hills T, Hui R, Hunt JF, Seetharaman J, Joachimiak A, Kennedy MA, Kim C, Lingel A, Michalska K, Montelione GT, Otero JM, Perrakis A, Pizarro JC, van Raaij MJ, Ramelot TA, Rousseau F, Tong L, Wernimont AK, Young J, Schwede T. Target highlights in CASP9: Experimental target structures for the critical assessment of techniques for protein structure prediction. Proteins 2011; 79 Suppl 10:6-20. [PMID: 22020785 PMCID: PMC3692002 DOI: 10.1002/prot.23196] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
One goal of the CASP community wide experiment on the critical assessment of techniques for protein structure prediction is to identify the current state of the art in protein structure prediction and modeling. A fundamental principle of CASP is blind prediction on a set of relevant protein targets, that is, the participating computational methods are tested on a common set of experimental target proteins, for which the experimental structures are not known at the time of modeling. Therefore, the CASP experiment would not have been possible without broad support of the experimental protein structural biology community. In this article, several experimental groups discuss the structures of the proteins which they provided as prediction targets for CASP9, highlighting structural and functional peculiarities of these structures: the long tail fiber protein gp37 from bacteriophage T4, the cyclic GMP-dependent protein kinase Iβ dimerization/docking domain, the ectodomain of the JTB (jumping translocation breakpoint) transmembrane receptor, Autotaxin in complex with an inhibitor, the DNA-binding J-binding protein 1 domain essential for biosynthesis and maintenance of DNA base-J (β-D-glucosyl-hydroxymethyluracil) in Trypanosoma and Leishmania, an so far uncharacterized 73 residue domain from Ruminococcus gnavus with a fold typical for PDZ-like domains, a domain from the phycobilisome core-membrane linker phycobiliprotein ApcE from Synechocystis, the heat shock protein 90 activators PFC0360w and PFC0270w from Plasmodium falciparum, and 2-oxo-3-deoxygalactonate kinase from Klebsiella pneumoniae.
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Affiliation(s)
- Andriy Kryshtafovych
- Genome Center, University of California-Davis, 451 Health Sciences Drive, Davis, CA 95616, USA
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Abstract
OBJECTIVE To evaluate the effectiveness of a peer-led asthma self-management program for adolescents. DESIGN Randomized controlled trial comparing a peer-led asthma program (intervention group) and a conventional adult-led asthma program (control group). Each program was implemented at a full-day camp. SETTING A city and adjacent suburbs in upstate New York. PARTICIPANTS A total of 112 adolescents aged 13 to 17 years with persistent asthma. INTERVENTION A peer-led asthma self-management program implemented at a day camp. MAIN OUTCOME MEASURES The Child Attitude Toward Illness Scale and the Paediatric Asthma Quality of Life Questionnaire were administered at baseline and immediately and 3, 6, and 9 months after the intervention. Spirometry was conducted twice: before and 9 months after the intervention. RESULTS The intervention group reported more positive attitudes at 6 months (mean difference, 4.11; 95% confidence interval [CI], 0.65-7.56) and higher quality of life at 6 months (difference, 11.38; 95% CI, 0.96-21.79) and 9 months (difference, 12.97; 95% CI, 3.46-22.48) than the control group. The intervention was found to be more beneficial to adolescents of male gender or low family income, as shown by greater improvement in positive attitudes toward asthma and quality of life than their counterparts. CONCLUSION An asthma self-management program led by peer leaders is a developmentally appropriate approach that can be effective in assisting adolescents with asthma in improving their attitudes and quality of life, particularly for males and those of low socioeconomic status. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01161225.
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Affiliation(s)
- Hyekyun Rhee
- University of Rochester, School of Nursing, Rochester, NY 14642, USA.
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50
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Gubellini F, Verdon G, Karpowich NK, Luff JD, Boël G, Gauthier N, Handelman SK, Ades SE, Hunt JF. Physiological response to membrane protein overexpression in E. coli. Mol Cell Proteomics 2011; 10:M111.007930. [PMID: 21719796 PMCID: PMC3205863 DOI: 10.1074/mcp.m111.007930] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Overexpression represents a principal bottleneck in structural and functional studies of integral membrane proteins (IMPs). Although E. coli remains the leading organism for convenient and economical protein overexpression, many IMPs exhibit toxicity on induction in this host and give low yields of properly folded protein. Different mechanisms related to membrane biogenesis and IMP folding have been proposed to contribute to these problems, but there is limited understanding of the physical and physiological constraints on IMP overexpression and folding in vivo. Therefore, we used a variety of genetic, genomic, and microscopy techniques to characterize the physiological responses of Escherichia coli MG1655 cells to overexpression of a set of soluble proteins and IMPs, including constructs exhibiting different levels of toxicity and producing different levels of properly folded versus misfolded product on induction. Genetic marker studies coupled with transcriptomic results indicate only minor perturbations in many of the physiological systems implicated in previous studies of IMP biogenesis. Overexpression of either IMPs or soluble proteins tends to block execution of the standard stationary-phase transcriptional program, although these effects are consistently stronger for the IMPs included in our study. However, these perturbations are not an impediment to successful protein overexpression. We present evidence that, at least for the target proteins included in our study, there is no inherent obstacle to IMP overexpression in E. coli at moderate levels suitable for structural studies and that the biochemical and conformational properties of the proteins themselves are the major obstacles to success. Toxicity associated with target protein activity produces selective pressure leading to preferential growth of cells harboring expression-reducing and inactivating mutations, which can produce chemical heterogeneity in the target protein population, potentially contributing to the difficulties encountered in IMP crystallization.
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Affiliation(s)
- Francesca Gubellini
- Department of Biological Sciences, 702A Fairchild Center, MC2434, Columbia University, New York, New York 10027, USA
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