1
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Elena-Real CA, Urbanek A, Imbert L, Morató A, Fournet A, Allemand F, Sibille N, Boisbouvier J, Bernadó P. Site-Specific Introduction of Alanines for the Nuclear Magnetic Resonance Investigation of Low-Complexity Regions and Large Biomolecular Assemblies. ACS Chem Biol 2023; 18:2039-2049. [PMID: 37582223 DOI: 10.1021/acschembio.3c00288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
Nuclear magnetic resonance (NMR) studies of large biomolecular machines and highly repetitive proteins remain challenging due to the difficulty of assigning frequencies to individual nuclei. Here, we present an efficient strategy to address this challenge by engineering a Pyrococcus horikoshii tRNA/alanyl-tRNA synthetase pair that enables the incorporation of up to three isotopically labeled alanine residues in a site-specific manner using in vitro protein expression. The general applicability of this approach for NMR assignment has been demonstrated by introducing isotopically labeled alanines into four distinct proteins: huntingtin exon-1, HMA8 ATPase, the 300 kDa molecular chaperone ClpP, and the alanine-rich Phox2B transcription factor. For large protein assemblies, our labeling approach enabled unambiguous assignments while avoiding potential artifacts induced by site-specific mutations. When applied to Phox2B, which contains two poly-alanine tracts of nine and twenty alanines, we observed that the helical stability is strongly dependent on the homorepeat length. The capacity to selectively introduce alanines with distinct labeling patterns is a powerful tool to probe structure and dynamics of challenging biomolecular systems.
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Affiliation(s)
- Carlos A Elena-Real
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 29 rue de Navacelles, 34090 Montpellier, France
| | - Annika Urbanek
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 29 rue de Navacelles, 34090 Montpellier, France
| | - Lionel Imbert
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France
| | - Anna Morató
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 29 rue de Navacelles, 34090 Montpellier, France
| | - Aurélie Fournet
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 29 rue de Navacelles, 34090 Montpellier, France
| | - Frédéric Allemand
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 29 rue de Navacelles, 34090 Montpellier, France
| | - Nathalie Sibille
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 29 rue de Navacelles, 34090 Montpellier, France
| | - Jérôme Boisbouvier
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71, avenue des martyrs, F-38044 Grenoble, France
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 29 rue de Navacelles, 34090 Montpellier, France
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2
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Jung KH, Sun J, Hsiung CH, Lance Lian X, Liu Y, Zhang X. Nuclear bodies protect phase separated proteins from degradation in stressed proteome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537522. [PMID: 37131610 PMCID: PMC10153235 DOI: 10.1101/2023.04.19.537522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
RNA-binding proteins (RBPs) containing intrinsically disordered domains undergo liquid-liquid phase separation to form nuclear bodies under stress conditions. This process is also connected to the misfolding and aggregation of RBPs, which are associated with a series of neurodegenerative diseases. However, it remains elusive how folding states of RBPs changes upon the formation and maturation of nuclear bodies. Here, we describe SNAP-tag based imaging methods to visualize the folding states of RBPs in live cells via time-resolved quantitative microscopic analyses of their micropolarity and microviscosity. Using these imaging methods in conjunction with immunofluorescence imaging, we demonstrate that RBPs, represented by TDP-43, initially enters the PML nuclear bodies in its native state upon transient proteostasis stress, albeit it begins to misfolded during prolonged stress. Furthermore, we show that heat shock protein 70 co-enters the PML nuclear bodies to prevent the degradation of TDP-43 from the proteotoxic stress, thus revealing a previously unappreciated protective role of the PML nuclear bodies in the prevention of stress-induced degradation of TDP-43. In summary, our imaging methods described in the manuscript, for the first time, reveal the folding states of RBPs, which were previously challenging to study with conventional methods in nuclear bodies of live cells. This study uncovers the mechanistic correlations between the folding states of a protein and functions of nuclear bodies, in particular PML bodies. We envision that the imaging methods can be generally applied to elucidating the structural aspects of other proteins that exhibit granular structures under biological stimulus.
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Affiliation(s)
- Kwan Ho Jung
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Jiarui Sun
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Chia-Heng Hsiung
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
- Present address: Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China; Westlake Laboratory of Life Sciences and Biomedicine; 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Department of Biomedical Engineering, The Huck Institute of Life Sciences, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Xiaojun Lance Lian
- Department of Biomedical Engineering, The Huck Institute of Life Sciences, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Yu Liu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
| | - Xin Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
- Present address: Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China; Westlake Laboratory of Life Sciences and Biomedicine; 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Department of Biomedical Engineering, The Huck Institute of Life Sciences, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
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3
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Engelhardt PM, Rueda SF, Drexelius M, Neudörfl JM, Lauster D, Hackenberger CPR, Kühne R, Neundorf I, Schmalz HG. Synthetic α-Helical Peptides as Potential Inhibitors of the ACE2 SARS-CoV-2 Interaction. Chembiochem 2022; 23:e202200372. [PMID: 35785462 PMCID: PMC9350387 DOI: 10.1002/cbic.202200372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/04/2022] [Indexed: 11/11/2022]
Abstract
During viral cell entry, the spike protein of SARS‐CoV‐2 binds to the α1‐helix motif of human angiotensin‐converting enzyme 2 (ACE2). Thus, alpha‐helical peptides mimicking this motif may serve as inhibitors of viral cell entry. For this purpose, we employed the rigidified diproline‐derived module ProM‐5 to induce α‐helicity in short peptide sequences inspired by the ACE2 α1‐helix. Starting with Ac‐QAKTFLDKFNHEAEDLFYQ‐NH2 as a relevant section of α1, a series of peptides, N‐capped with either Ac‐βHAsp‐[ProM‐5] or Ac‐βHAsp‐PP, were prepared and their α‐helicities were investigated. While ProM‐5 clearly showed a pronounced effect, an even increased degree of helicity (up to 63 %) was observed in sequences in which non‐binding amino acids were replaced by alanine. The binding affinities of the peptides towards the spike protein, as determined by means of microscale thermophoresis (MST), revealed only a subtle influence of the α‐helical content and, noteworthy, led to the identification of an Ac‐βHAsp‐PP‐capped peptide displaying a very strong binding affinity (KD=62 nM).
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Affiliation(s)
| | - Sebastián Florez Rueda
- FMP: Leibniz-Forschungsinstitut fur Molekulare Pharmakologie im Forschungsverbund Berlin eV, chemical biology, GERMANY
| | - Marco Drexelius
- University of Cologne: Universitat zu Koln, Chemistry, GERMANY
| | | | - Daniel Lauster
- Freie Universitat Berlin Fachbereich Biologie Chemie Pharmazie, biochemistry and chemistry, GERMANY
| | - Christian P R Hackenberger
- FMP: Leibniz-Forschungsinstitut fur Molekulare Pharmakologie im Forschungsverbund Berlin eV, chemical biology, GERMANY
| | - Ronald Kühne
- FMP: Leibniz-Forschungsinstitut fur Molekulare Pharmakologie im Forschungsverbund Berlin eV, drug discovery, GERMANY
| | - Ines Neundorf
- University of Cologne: Universitat zu Koln, chemistry and biochemistry, GERMANY
| | - Hans-Günther Schmalz
- Universitat zu Koln, Department für Chemie, Greinstrasse 4, 50939, Köln, GERMANY
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4
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Cobb J, Zai-Rose V, Correia JJ, Janorkar AV. FT-IR Spectroscopic Analysis of the Secondary Structures Present during the Desiccation Induced Aggregation of Elastin-Like Polypeptide on Silica. ACS OMEGA 2020; 5:8403-8413. [PMID: 32309751 PMCID: PMC7161207 DOI: 10.1021/acsomega.0c00271] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/06/2020] [Indexed: 05/25/2023]
Abstract
Previously, we found that elastin-like polypeptide (ELP), when dried above the lower critical solution temperature on top of a hydrophilic fused silica disk, exhibited a dynamic coalescence behavior. The ELP initially wet the silica, but over the next 12 h, dewett the surface and formed aggregates of precise sizes and shapes. Using Fourier-transform infrared (FT-IR) spectroscopy, the present study explores the role of secondary structures present in ELP during this progressive desiccation and their effect on aggregate size. The amide I peak (1600-1700 cm-1) in the ELP's FT-IR spectrum was deconvoluted using the second derivative method into eight subpeaks (1616, 1624, 1635, 1647, 1657, 1666, 1680, 1695 cm-1). These peaks were identified to represent extended strands, β-turns, 3(10)-helix, polyproline I, and polyproline II using previous studies on ELP and molecules similar in peptide composition. Positive correlations were established between the various subpeaks, water content, and aggregate size to understand the contributions of the secondary structures in particle formation. The positive correlations suggest that type II β-turns, independent of the water content, contributed to the growth of the aggregates at earlier time points (1-3.5 h). At later time points (6-12 h), the aggregate growth was attributed to the formation of 3(10)-helices that relied on a decrease in water content. Understanding these relationships gives greater control in creating precisely sized aggregates and surface coatings with varying roughness.
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Affiliation(s)
- Jared
S. Cobb
- Department
of Biomedical Materials Science, School of Dentistry and Department of
Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, Mississippi 39216, United States
| | - Valeria Zai-Rose
- Department
of Biomedical Materials Science, School of Dentistry and Department of
Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, Mississippi 39216, United States
| | - John J. Correia
- Department
of Biomedical Materials Science, School of Dentistry and Department of
Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, Mississippi 39216, United States
| | - Amol V. Janorkar
- Department
of Biomedical Materials Science, School of Dentistry and Department of
Cell and Molecular Biology, School of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, Mississippi 39216, United States
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Kamp F, Scheidt HA, Winkler E, Basset G, Heinel H, Hutchison JM, LaPointe LM, Sanders CR, Steiner H, Huster D. Bexarotene Binds to the Amyloid Precursor Protein Transmembrane Domain, Alters Its α-Helical Conformation, and Inhibits γ-Secretase Nonselectively in Liposomes. ACS Chem Neurosci 2018; 9:1702-1713. [PMID: 29717863 DOI: 10.1021/acschemneuro.8b00068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bexarotene is a pleiotropic molecule that has been proposed as an amyloid-β (Aβ)-lowering drug for the treatment of Alzheimer's disease (AD). It acts by upregulation of an apolipoprotein E (apoE)-mediated Aβ clearance mechanism. However, whether bexarotene induces removal of Aβ plaques in mouse models of AD has been controversial. Here, we show by NMR and CD spectroscopy that bexarotene directly interacts with and stabilizes the transmembrane domain α-helix of the amyloid precursor protein (APP) in a region where cholesterol binds. This effect is not mediated by changes in membrane lipid packing, as bexarotene does not share with cholesterol the property of inducing phospholipid condensation. Bexarotene inhibited the intramembrane cleavage by γ-secretase of the APP C-terminal fragment C99 to release Aβ in cell-free assays of the reconstituted enzyme in liposomes, but not in cells, and only at very high micromolar concentrations. Surprisingly, in vitro, bexarotene also inhibited the cleavage of Notch1, another major γ-secretase substrate, demonstrating that its inhibition of γ-secretase is not substrate specific and not mediated by acting via the cholesterol binding site of C99. Our data suggest that bexarotene is a pleiotropic molecule that interfere with Aβ metabolism through multiple mechanisms.
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Affiliation(s)
- Frits Kamp
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
| | - Holger A. Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - Edith Winkler
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
| | - Gabriele Basset
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
| | - Hannes Heinel
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - James M. Hutchison
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Loren M. LaPointe
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Charles R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Harald Steiner
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
- German Center for Neurodegenerative Diseases (DZNE)−Munich, Feodor-Lynen-Str. 17, D-81377 Munich, Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
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6
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Goyal B, Srivastava KR, Durani S. N-terminal diproline and charge group effects on the stabilization of helical conformation in alanine-based short peptides: CD studies with water and methanol as solvent. J Pept Sci 2017; 23:431-437. [PMID: 28425159 DOI: 10.1002/psc.3005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/17/2017] [Accepted: 03/20/2017] [Indexed: 12/25/2022]
Abstract
Protein folding problem remains a formidable challenge as main chain, side chain and solvent interactions remain entangled and have been difficult to resolve. Alanine-based short peptides are promising models to dissect protein folding initiation and propagation structurally as well as energetically. The effect of N-terminal diproline and charged side chains is assessed on the stabilization of helical conformation in alanine-based short peptides using circular dichroism (CD) with water and methanol as solvent. A1 (Ac-Pro-Pro-Ala-Lys-Ala-Lys-Ala-Lys-Ala-NH2 ) is designed to assess the effect of N-terminal homochiral diproline and lysine side chains to induce helical conformation. A2 (Ac-Pro-Pro-Glu-Glu-Ala-Ala-Lys-Lys-Ala-NH2 ) and A3 (Ac-dPro-Pro-Glu-Glu-Ala-Ala-Lys-Lys-Ala-NH2 ) with N-terminal homochiral and heterochiral diproline, respectively, are designed to assess the effect of Glu...Lys (i, i + 4) salt bridge interactions on the stabilization of helical conformation. The CD spectra of A1, A2 and A3 in water manifest different amplitudes of the observed polyproline II (PPII) signals, which indicate different conformational distributions of the polypeptide structure. The strong effect of solvent substitution from water to methanol is observed for the peptides, and CD spectra in methanol evidence A2 and A3 as helical folds. Temperature-dependent CD spectra of A1 and A2 in water depict an isodichroic point reflecting coexistence of two conformations, PPII and β-strand conformation, which is consistent with the previous studies. The results illuminate the effect of N-terminal diproline and charged side chains in dictating the preferences for extended-β, semi-extended PPII and helical conformation in alanine-based short peptides. The results of the present study will enhance our understanding on stabilization of helical conformation in short peptides and hence aid in the design of novel peptides with helical structures. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.
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Affiliation(s)
- Bhupesh Goyal
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.,Department of Chemistry, School of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib, 140406, Punjab, India
| | - Kinshuk Raj Srivastava
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.,Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Susheel Durani
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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7
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Dexter AF, Fletcher N, Creasey RG, Filardo F, Boehm MW, Jack KS. Fabrication and characterization of hydrogels formed from designer coiled-coil fibril-forming peptides. RSC Adv 2017. [DOI: 10.1039/c7ra02811c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
A peptide sequence was designed to form α-helical fibrils and hydrogels at physiological pH, utilising transient buffering by carbonic acid.
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Affiliation(s)
- A. F. Dexter
- The University of Queensland
- Australian Institute for Bioengineering and Biotechnology
- Australia
| | - N. L. Fletcher
- The University of Queensland
- Australian Institute for Bioengineering and Biotechnology
- Australia
| | - R. G. Creasey
- The University of Queensland
- School of Chemical Engineering
- Australia
| | - F. Filardo
- The University of Queensland
- Australian Institute for Bioengineering and Biotechnology
- Australia
| | - M. W. Boehm
- The University of Queensland
- School of Chemical Engineering
- Australia
| | - K. S. Jack
- The University of Queensland
- Centre for Microscopy and Microanalysis
- Australia
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8
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Goyal B, Srivastava KR, Durani S. Examination of the Effect of N-terminal Diproline and Charged Side Chains on the Stabilization of Helical Conformation in Alanine-based Short Peptides: A Molecular Dynamics Study. ChemistrySelect 2016. [DOI: 10.1002/slct.201601381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Bhupesh Goyal
- Department of Chemistry; Indian Institute of Technology Bombay, Powai; Mumbai-400076 India
- Department of Chemistry; School of Basic and Applied Sciences; Sri Guru Granth Sahib World University, Fatehgarh; Sahib-140406, Punjab India
| | - Kinshuk Raj Srivastava
- Department of Chemistry; Indian Institute of Technology Bombay, Powai; Mumbai-400076 India
- Life Sciences Institute; University of Michigan; Ann Arbor, MI USA 48105
| | - Susheel Durani
- Department of Chemistry; Indian Institute of Technology Bombay, Powai; Mumbai-400076 India
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9
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McLachlan GD, Gandjian B, Alhumaidan H. Folding recombinant spider-silk in H2 O: Effect of osmolytes on the solution conformation of a 15-repeat spider-silk mimetic. Protein Sci 2016; 25:1853-62. [PMID: 27488926 PMCID: PMC5029536 DOI: 10.1002/pro.2995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/30/2016] [Accepted: 08/01/2016] [Indexed: 11/10/2022]
Abstract
The folding of a recombinant spider silk protein-polymer in the presence of the tri-methylamine osmolytes TMANO and Betaine in 80% H2 O is reported. Circular dichroism measurements (CD) reveal an increase in α-helical secondary structure with increasing osmolyte concentrations, as determined by an increase in ellipticity at 222 nm. Consistent with this observation, the signal for random coil sampling, observed at 205 nm, is greatly reduced with increasing trimethylamine. Fluorescence spectra of a single tyrosine positioned within the conserved 33-amino acid repeat primary sequence (of the spider-silk mimetic) complements the conformational changes observed by CD. Importantly, there is a correlation between the number of Alkyl-groups (CH3 -) on the amine of the osmolyte and enhanced helicity of the 15-repeat silk-mimetic for the osmolytes tested, ie TMANO, Betaine, Sarcosine and Glycine. These preliminary results are applicable to storing and processing recombinant silk sequences in H2 O, an important mile-stone for widespread use of recombinant silk polymers.
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Affiliation(s)
- Glendon D McLachlan
- Department of Chemistry and Biochemistry Queens College, CUNY, Flushing, NY, 11367.
| | - Babak Gandjian
- Department of Chemistry and Biochemistry Queens College, CUNY, Flushing, NY, 11367
| | - Hind Alhumaidan
- Department of Chemistry and Biochemistry Queens College, CUNY, Flushing, NY, 11367
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10
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Hoang HN, Driver RW, Beyer RL, Hill TA, D. de Araujo A, Plisson F, Harrison RS, Goedecke L, Shepherd NE, Fairlie DP. Helix Nucleation by the Smallest Known α‐Helix in Water. Angew Chem Int Ed Engl 2016; 55:8275-9. [DOI: 10.1002/anie.201602079] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Huy N. Hoang
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Russell W. Driver
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Renée L. Beyer
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Timothy A. Hill
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Aline D. de Araujo
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Fabien Plisson
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Rosemary S. Harrison
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Lena Goedecke
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Nicholas E. Shepherd
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - David P. Fairlie
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
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11
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Hoang HN, Driver RW, Beyer RL, Hill TA, D. de Araujo A, Plisson F, Harrison RS, Goedecke L, Shepherd NE, Fairlie DP. Helix Nucleation by the Smallest Known α‐Helix in Water. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201602079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Huy N. Hoang
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Russell W. Driver
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Renée L. Beyer
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Timothy A. Hill
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Aline D. de Araujo
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Fabien Plisson
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Rosemary S. Harrison
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Lena Goedecke
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Nicholas E. Shepherd
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - David P. Fairlie
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
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12
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Okur A, Wickstrom L, Layten M, Geney R, Song K, Hornak V, Simmerling C. Improved Efficiency of Replica Exchange Simulations through Use of a Hybrid Explicit/Implicit Solvation Model. J Chem Theory Comput 2015; 2:420-33. [PMID: 26626529 DOI: 10.1021/ct050196z] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of parallel tempering or replica exchange molecular dynamics (REMD) simulations has facilitated the exploration of free energy landscapes for complex molecular systems, but application to large systems is hampered by the scaling of the number of required replicas with increasing system size. Use of continuum solvent models reduces system size and replica requirements, but these have been shown to provide poor results in many cases, including overstabilization of ion pairs and secondary structure bias. Hybrid explicit/continuum solvent models can overcome some of these problems through an explicit representation of water molecules in the first solvation shells, but these methods typically require restraints on the solvent molecules and show artifacts in water properties due to the solvation interface. We propose an REMD variant in which the simulations are performed with a fully explicit solvent, but the calculation of exchange probability is carried out using a hybrid model, with the solvation shells calculated on the fly during the fully solvated simulation. The resulting reduction in the perceived system size in the REMD exchange calculation provides a dramatic decrease in the computational cost of REMD, while maintaining a very good agreement with results obtained from the standard explicit solvent REMD. We applied several standard and hybrid REMD methods with different solvent models to alanine polymers of 1, 3, and 10 residues, obtaining ensembles that were essentially independent of the initial conformation, even with explicit solvation. Use of only a continuum model without a shell of explicit water provided poor results for Ala3 and Ala10, with a significant bias in favor of the α-helix. Likewise, using only the solvation shells and no continuum model resulted in ensembles that differed significantly from the standard explicit solvent data. Ensembles obtained from hybrid REMD are in very close agreement with explicit solvent data, predominantly populating polyproline II conformations. Inclusion of a second shell of explicit solvent was found to be unnecessary for these peptides.
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Affiliation(s)
- Asim Okur
- Department of Chemistry, Graduate Program in Biochemistry and Structural Biology, Graduate Program in Molecular and Cellular Biology, and Center for Structural Biology, Stony Brook University, Stony Brook, New York 11794, and Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973
| | - Lauren Wickstrom
- Department of Chemistry, Graduate Program in Biochemistry and Structural Biology, Graduate Program in Molecular and Cellular Biology, and Center for Structural Biology, Stony Brook University, Stony Brook, New York 11794, and Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973
| | - Melinda Layten
- Department of Chemistry, Graduate Program in Biochemistry and Structural Biology, Graduate Program in Molecular and Cellular Biology, and Center for Structural Biology, Stony Brook University, Stony Brook, New York 11794, and Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973
| | - Raphäel Geney
- Department of Chemistry, Graduate Program in Biochemistry and Structural Biology, Graduate Program in Molecular and Cellular Biology, and Center for Structural Biology, Stony Brook University, Stony Brook, New York 11794, and Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973
| | - Kun Song
- Department of Chemistry, Graduate Program in Biochemistry and Structural Biology, Graduate Program in Molecular and Cellular Biology, and Center for Structural Biology, Stony Brook University, Stony Brook, New York 11794, and Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973
| | - Viktor Hornak
- Department of Chemistry, Graduate Program in Biochemistry and Structural Biology, Graduate Program in Molecular and Cellular Biology, and Center for Structural Biology, Stony Brook University, Stony Brook, New York 11794, and Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973
| | - Carlos Simmerling
- Department of Chemistry, Graduate Program in Biochemistry and Structural Biology, Graduate Program in Molecular and Cellular Biology, and Center for Structural Biology, Stony Brook University, Stony Brook, New York 11794, and Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973
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13
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Abstract
Although nonflexible, scaled molecular models like Pauling-Corey's and its descendants have made significant contributions in structural biology research and pedagogy, recent technical advances in 3D printing and electronics make it possible to go one step further in designing physical models of biomacromolecules: to make them conformationally dynamic. We report here the design, construction, and validation of a flexible, scaled, physical model of the polypeptide chain, which accurately reproduces the bond rotational degrees of freedom in the peptide backbone. The coarse-grained backbone model consists of repeating amide and α-carbon units, connected by mechanical bonds (corresponding to ϕ and ψ) that include realistic barriers to rotation that closely approximate those found at the molecular scale. Longer-range hydrogen-bonding interactions are also incorporated, allowing the chain to readily fold into stable secondary structures. The model is easily constructed with readily obtainable parts and promises to be a tremendous educational aid to the intuitive understanding of chain folding as the basis for macromolecular structure. Furthermore, this physical model can serve as the basis for linking tangible biomacromolecular models directly to the vast array of existing computational tools to provide an enhanced and interactive human-computer interface.
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14
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Hack V, Reuter C, Opitz R, Schmieder P, Beyermann M, Neudörfl JM, Kühne R, Schmalz HG. Efficient α-Helix Induction in a Linear Peptide Chain byN-Capping with a Bridged-tricyclic Diproline Analogue. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Hack V, Reuter C, Opitz R, Schmieder P, Beyermann M, Neudörfl JM, Kühne R, Schmalz HG. Efficient α-Helix Induction in a Linear Peptide Chain byN-Capping with a Bridged-tricyclic Diproline Analogue. Angew Chem Int Ed Engl 2013; 52:9539-43. [DOI: 10.1002/anie.201302014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Revised: 04/11/2013] [Indexed: 11/11/2022]
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16
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Bernacki JP, Murphy RM. Length-dependent aggregation of uninterrupted polyalanine peptides. Biochemistry 2011; 50:9200-11. [PMID: 21932820 DOI: 10.1021/bi201155g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polyalanine (polyA) is the third-most prevalent homopeptide repeat in eukaryotes, behind polyglutamine and polyasparagine. Abnormal expansion of the polyA repeat is linked to at least nine human diseases, and the disease mechanism likely involves enhanced length-dependent aggregation. Because of the simplicity of its side chain, polyA has been a favorite target of computational studies, and because of their tendency to fold into α-helix, peptides containing polyA-rich domains have been a popular experimental subject. However, experimental studies on uninterrupted polyA are very limited. We synthesized polyA peptides containing uninterrupted sequences of 7 to 25 alanines (A7 to A25) and characterized their length-dependent conformation and aggregation properties. The peptides were primarily disordered, with a modest component of α-helix that increased with increasing length. From measurements of mean distance spanned by the polyA segment, we concluded that physiological buffers are neutral solvents for shorter polyA peptides and poor solvents for longer peptides. At moderate concentration and near-physiological temperature, polyA assembled into soluble oligomers, with a sharp transition in oligomer physical properties between A19 and A25. With A19, oligomers were large, contained only a small fraction of the total peptide mass, and slowly grew into loose clusters, while A25 rapidly and completely assembled into small stable oligomers of ~7 nm radius. At high temperatures, A19 assembled into fibrils, but A25 precipitated as dense, micrometer-sized particles. A comparison of these results to those obtained with polyglutamine peptides of similar design sheds light on the role of the side chain in regulating conformation and aggregation.
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Affiliation(s)
- Joseph P Bernacki
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
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17
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Nasr KA, Schubert CR, Török M, Kennedy RJ, Kemp DS. Helix-coil energetics for helix formers and breakers reflect context and temperature: mutants of helically robust, guest-sensitive homopeptide hosts. Biopolymers 2010; 91:311-20. [PMID: 19117030 DOI: 10.1002/bip.21129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The natural amino acids are primarily helix breakers at the low assignment temperatures characteristic of many studies, but recent genomic analyses of thermophilic proteins suggest that at high temperatures, some breakers may become strong helix formers. Moreover, the breaker/former inventory has not been previously characterized at the physiologically relevant temperature of 37 degrees C. The versatility of 13C==O NMR chemical shifts as helicity reporters allows construction of two mutant peptide series, tailored to expand the range of temperature assignments for helical propensities and derived from the core hosts tL-Ala9XxxAla9-tL and tL-AlaNva4XxxNva4Ala9-tL, Nva=norvaline. For three limiting guests Xxx, the helix former Nva and the breakers Gly and Pro, we report wXxx[T] assignments at seven temperatures from 2 to 80 degrees C, validating our reasoning and paving the way for assignment of a definitive wXxx[T] data-base.
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Affiliation(s)
- Khaled A Nasr
- Department of Chemistry, Room 6-433, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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18
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Bellesia G, Jewett AI, Shea JE. Sequence periodicity and secondary structure propensity in model proteins. Protein Sci 2010; 19:141-54. [PMID: 19937649 DOI: 10.1002/pro.288] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We explore the question of whether local effects (originating from the amino acids intrinsic secondary structure propensities) or nonlocal effects (reflecting the sequence of amino acids as a whole) play a larger role in determining the fold of globular proteins. Earlier circular dichroism studies have shown that the pattern of polar, non polar amino acids (nonlocal effect) dominates over the amino acid intrinsic propensity (local effect) in determining the secondary structure of oligomeric peptides. In this article, we present a coarse grained computational model that allows us to quantitatively estimate the role of local and nonlocal factors in determining both the secondary and tertiary structure of small, globular proteins. The amino acid intrinsic secondary structure propensity is modeled by a dihedral potential term. This dihedral potential is parametrized to match with experimental measurements of secondary structure propensity. Similarly, the magnitude of the attraction between hydrophobic residues is parametrized to match the experimental transfer free energies of hydrophobic amino acids. Under these parametrization conditions, we systematically explore the degree of frustration a given polar, non polar pattern can tolerate when the secondary structure intrinsic propensities are in opposition to it. When the parameters are in the biophysically relevant range, we observe that the fold of small, globular proteins is determined by the pattern of polar, non polar amino acids regardless of their instrinsic secondary structure propensities. Our simulations shed new light on previous observations that tertiary interactions are more influential in determining protein structure than secondary structure propensity. The fact that this can be inferred using a simple polymer model that lacks most of the biochemical details points to the fundamental importance of binary patterning in governing folding.
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Affiliation(s)
- Giovanni Bellesia
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
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19
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Kantharaju, Raghothama S, Aravinda S, Shamala N, Balaram P. Helical conformations of hexapeptides containing N-terminus diproline segments. Biopolymers 2010; 94:360-70. [DOI: 10.1002/bip.21395] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Moreau RJ, Schubert CR, Nasr KA, Török M, Miller JS, Kennedy RJ, Kemp DS. Context-independent, temperature-dependent helical propensities for amino acid residues. J Am Chem Soc 2009; 131:13107-16. [PMID: 19702302 PMCID: PMC2770013 DOI: 10.1021/ja904271k] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Assigned from data sets measured in water at 2, 25, and 60 degrees C containing (13)C=O NMR chemical shifts and [theta](222) ellipticities, helical propensities are reported for the 20 genetically coded amino acids, as well as for norvaline and norleucine. These have been introduced by chemical synthesis at central sites within length-optimized, spaced, solubilized Ala(19) hosts. The resulting polyalanine-derived, quantitative propensity sets express for each residue its temperature-dependent but context-independent tendency to forego a coil state and join a preexisting helical conformation. At 2 degrees C their rank ordering is: P << G < H < C, T, N < S < Y, F, W < V, D < K < Q < I < R, M < L < E < A; at 60 degrees C the rank becomes: H, P < G < C < R, K < T, Y, F < N, V < S < Q < W, D < I, M < E < A < L. The DeltaDeltaG values, kcal/mol, relative to alanine, for the cluster T, N, S, Y, F, W, V, D, Q, imply that at 2 degrees C all are strong breakers: DeltaDeltaG(mean) = +0.63 +/- 0.11, but at 60 degrees C their breaking tendencies are dramatically attenuated and converge toward the mean: DeltaDeltaG(mean) = +0.25 +/- 0.07. Accurate modeling of helix-rich proteins found in thermophiles, mesophiles, and organisms that flourish near 0 degrees C thus requires appropriately matched propensity sets. Comparisons are offered between the temperature-dependent propensity assignments of this study and those previously assigned by the Scheraga group; the special problems that attend propensity assignments for charged residues are illustrated by lysine guest data; and comparisons of errors in helicity assignments from shifts and ellipticity data show that the former provide superior precision and accuracy.
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Affiliation(s)
- Robert J Moreau
- Department of Chemistry, Room 6-433, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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21
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Saha I, Chatterjee B, Shamala N, Balaram P. Crystal structures of peptide enantiomers and racemates: probing conformational diversity in heterochiral Pro-Pro sequences. Biopolymers 2009; 90:537-43. [PMID: 18335426 DOI: 10.1002/bip.20982] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Multiple conformational states in heterochiral diproline sequences have been characterized in the solid state by the determination of the crystal structures of seven tripeptides in enantiomeric and racemic forms. The sequences of the type Piv-DPro-LPro-DXxx-NHMe (D-L-D) [DXxx=DVal 1, DLeu 3, and DPhe 5] and their corresponding enatiomeric L-D-L sequences [LXxx=LVal 2, LLeu 4, and LPhe 6] have been investigated. Single crystals have been obtained for the pure enantiomers 1, 2, 3, 4 and for the racemates 1/2, 3/4, and 5/6. For Xxx=Leu, mirror image conformations (type II/II' beta-turns) at Pro-Leu segment are obtained. For Xxx=Val, a LPro-DPro type II beta-turn in 2 and an open/extended structure is obtained in the solvated form of the enantiomer 1. For Xxx=Phe, suitable crystals could not be obtained for enatiomeric peptides. The racemate 5/6 revealed a cis peptide bond between the diproline segment with the absence of any intramolecular hydrogen bonds. Crystal structures of enantiomers and racemates prove useful in characterizing the multiple conformational states that are accessible to Pro-Pro segments.
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Affiliation(s)
- Indranil Saha
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
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22
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Kantharaju, Raghothama S, Raghavender US, Aravinda S, Shamala N, Balaram P. Conformations of heterochiral and homochiral proline-pseudoproline segments in peptides: Context dependentcis-transpeptide bond isomerization. Biopolymers 2009; 92:405-16. [DOI: 10.1002/bip.21207] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Chatterjee B, Saha I, Raghothama S, Aravinda S, Rai R, Shamala N, Balaram P. Designed peptides with homochiral and heterochiral diproline templates as conformational constraints. Chemistry 2008; 14:6192-204. [PMID: 18491347 DOI: 10.1002/chem.200702029] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Diproline segments have been advanced as templates for nucleation of folded structure in designed peptides. The conformational space available to homochiral and heterochiral diproline segments has been probed by crystallographic and NMR studies on model peptides containing L-Pro-L-Pro and D-Pro-L-Pro units. Four distinct classes of model peptides have been investigated: a) isolated D-Pro-L-Pro segments which form type II' beta-turn; b) D-Pro-L-Pro-L-Xxx sequences which form type II'-I (betaII'-I, consecutive beta-turns) turns; c) D-Pro-L-Pro-D-Xxx sequences; d) L-Pro-L-Pro-L-Xxx sequences. A total of 17 peptide crystal structures containing diproline segments are reported. Peptides of the type Piv-D-Pro-L-Pro-L-Xxx-NHMe are conformationally homogeneous, adopting consecutive beta-turn conformations. Peptides in the series Piv-D-Pro-L-Pro-D-Xxx-NHMe and Piv-L-Pro-L-Pro-L-Xxx-NHMe, display a heterogeneity of structures in crystals. A type VIa beta-turn conformation is characterized in Piv-L-Pro-L-Pro-L-Phe-OMe (18), while an example of a 5-->1 hydrogen bonded alpha-turn is observed in crystals of Piv-D-Pro-L-Pro-D-Ala-NHMe (11). An analysis of pyrrolidine conformations suggests a preferred proline puckering geometry is favored only in the case of heterochiral diproline segments. Solution NMR studies, reveal a strong conformational influence of the C-terminal Xxx residues on the structures of diproline segments. In L-Pro-L-Pro-L-Xxx sequences, the Xxx residues strongly determine the population of Pro-Pro cis conformers, with an overwhelming population of the trans form in L-Xxx=L-Ala (19).
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Affiliation(s)
- Bhaswati Chatterjee
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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24
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Abstract
We present a new computational methodology aimed to calculate the thermodynamics and kinetics of peptide folding. We focus in particular on temperature jump experiments of folding rates and show how a combination of replica exchange molecular dynamics (REMD) followed by multiplexed molecular dynamics starting from structures taken from the REMD runs can be used to extract properties in line with experiments. A model system, alanine20, is studied in this article as a proof of principle and used to describe the methodology.
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Affiliation(s)
- Seonah Kim
- Department of Chemistry and Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA
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25
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De Gortari I, Galván M, Ireta J, Segall M, Pickard CJ, Payne M. Theoretical Investigations of Oxygen-17 NMR Chemical Shifts to Discriminate among Helical Forms. J Phys Chem A 2007; 111:13099-105. [DOI: 10.1021/jp0751817] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Itzam De Gortari
- TCM Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom, Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, A.P. 55-534, México 09340, and Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweb 4-6, D-14195 Berlin-Dahlem, Germany
| | - Marcelo Galván
- TCM Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom, Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, A.P. 55-534, México 09340, and Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweb 4-6, D-14195 Berlin-Dahlem, Germany
| | - Joel Ireta
- TCM Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom, Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, A.P. 55-534, México 09340, and Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweb 4-6, D-14195 Berlin-Dahlem, Germany
| | - Matthew Segall
- TCM Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom, Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, A.P. 55-534, México 09340, and Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweb 4-6, D-14195 Berlin-Dahlem, Germany
| | - Chris J. Pickard
- TCM Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom, Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, A.P. 55-534, México 09340, and Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweb 4-6, D-14195 Berlin-Dahlem, Germany
| | - Mike Payne
- TCM Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom, Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, A.P. 55-534, México 09340, and Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweb 4-6, D-14195 Berlin-Dahlem, Germany
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26
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Garner J, Harding MM. Design and synthesis of alpha-helical peptides and mimetics. Org Biomol Chem 2007; 5:3577-85. [PMID: 17971985 DOI: 10.1039/b710425a] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The alpha-helix is the most abundant secondary structural element in proteins and is an important structural domain for mediating protein-protein and protein-nucleic acid interactions. Strategies for the rational design and synthesis of alpha-helix mimetics have not matured as well as other secondary structure mimetics such as strands and turns. This perspective will focus on developments in the design, synthesis and applications of alpha-helices and mimetics, particularly in the last 5 years. Examples where synthetic compounds have delivered promising biological results will be highlighted as well as opportunities for the design of mimetics of the type I alpha-helical antifreeze proteins.
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Affiliation(s)
- James Garner
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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27
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Job GE, Kennedy RJ, Heitmann B, Miller JS, Walker SM, Kemp* DS. Temperature- and length-dependent energetics of formation for polyalanine helices in water: assignment of w(Ala)(n,T) and temperature-dependent CD ellipticity standards. J Am Chem Soc 2007; 128:8227-33. [PMID: 16787087 PMCID: PMC1560101 DOI: 10.1021/ja060094y] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Length-dependent helical propensities w(Ala)(n,T) at T = 10, 25, and 60 degrees C are assigned from t/c values and NMR 13C chemical shifts for series 1 peptides TrpLys(m)Inp2(t)Leu-Ala(n)(t)LeuInp2Lys(m)NH2, n = 15, 19, and 25, m = 5, in water. Van't Hoff analysis of w(Ala)(n,T) show that alpha-helix formation is primarily enthalpy-driven. For series 2 peptides Ac-Trp Lys5Inp2(t)Leu-(beta)AspHel-Ala(n)-beta-(t)LeuInp2Lys5NH2, n = 12 and 22, which contain exceptionally helical Ala(n) cores, protection factor-derived fractional helicities FH are assigned in the range 10-30 degrees C in water and used to calibrate temperature-dependent CD ellipticities [theta](lambda,H,n,T). These are applied to CD data for series 1 peptides, 12 < or = n < or = 45, to confirm the w(Ala)(n,T) assignments at T = 25 and 60 degrees C. The [theta](lambda,H,n,T) are temperature dependent within the wavelength region, 222 +/- 12 nm, and yield a temperature correction for calculation of FH from experimental values of [theta](222,n,T,Exp).
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28
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Salvador P, Asensio A, Dannenberg JJ. The Effect of Aqueous Solvation upon α-Helix Formation for Polyalanines. J Phys Chem B 2007; 111:7462-6. [PMID: 17552560 DOI: 10.1021/jp071899a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The incremental free energies of aqueous solution for acetyl(ala)NNH2 in its extended unfolded and alpha-helical conformations are compared using the SM5.2 solvation method of Cramer and Truhlar. A combination of density functional theory (DFT) at the B3LYP/D95(d,p) and AM1 has been employed using the ONIOM method. The incremental solvation energies of alpha-helical structures are very similar for both ONIOM and AM1 optimized structures as these structures do not significantly change upon solution. However, the conformations of the unfolded peptides change from extended beta-strand to polyproline II conformations upon aqueous solution. The incremental solvation free energy per residue of the polyproline II structure is about 2 kcal/mol/residue greater than that for the alpha-helix, representing an upper limit for the difference between the solvation energies. However, most of this difference disappears when the energy required to distort the optimized gas-phase extended beta-strand structure to the optimized polyproline II solution structure is included in the analysis, leaving an estimated difference in incremental solvation free energy of 0.3-0.5 kcal/mol favoring the unfolded structure. The solution structure sacrifices the stability derived from the intramolecular C5 H-bonds for more favorable interactions with the aqueous solvent.
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Affiliation(s)
- Pedro Salvador
- Department of Chemistry, City University of New York, Hunter College and the Graduate School, New York, New York 10021, USA
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29
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Toward the Design of Highly Efficient, Readily Accessible Peptide N-caps for the Induction of Helical Conformations. Int J Pept Res Ther 2007. [DOI: 10.1007/s10989-006-9073-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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30
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Mikhonin AV, Asher SA, Bykov SV, Murza A. UV Raman spatially resolved melting dynamics of isotopically labeled polyalanyl peptide: slow alpha-helix melting follows 3(10)-helices and pi-bulges premelting. J Phys Chem B 2007; 111:3280-92. [PMID: 17388440 DOI: 10.1021/jp0654009] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We used UV resonance Raman (UVRR) to examine the spatial dependence of the T-jump secondary structure relaxation of an isotopically labeled 21-residue mainly Ala peptide, AdP. The AdP penultimate Ala residues were perdeuterated, leaving the central residues hydrogenated, to allow separate monitoring of melting of the middle versus the end peptide bonds. For 5 to 30 degrees C T-jumps, the central peptide bonds show a approximately 2-fold slower relaxation time (189 +/- 31 ns) than do the exterior peptide bonds (97 +/- 15 ns). In contrast, for a 20 to 40 degrees C T-jump, the central peptide bond relaxation appears to be faster (56 +/- 6 ns) than that of the penultimate peptide bonds (131 +/- 46 ns). We show that, if the data are modeled as a two-state transition, we find that only exterior peptide bonds show anti-Arrhenius folding behavior; the middle peptide bonds show both normal Arrhenius-like folding and unfolding. This anti-Arrhenius behavior results from the involvement of pi-bulges/helices and 3(10)-helix states in the melting. The unusual temperature dependence of the (un)folding rates of the interior and exterior peptide bonds is due to the different relative (un)folding rates of 3(10)-helices, alpha-helices, and pi-bulges/helices. Pure alpha-helix unfolding rates are approximately 12-fold slower (approximately 1 micros) than that of pi-bulges and 3(10)-helices. In addition, we also find that the alpha-helix is most stable at the AdP N-terminus where eight consecutive Ala occur, whereas the three hydrophilic Arg located in the middle and at the C-terminus destabilize the alpha-helix in these regions and induce defects such as pi-bulges and 3(10)-helices.
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Affiliation(s)
- Aleksandr V Mikhonin
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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Salvador P, Wieczorek R, Dannenberg JJ. Direct Calculation of trans-Hydrogen-Bond 13C-15N 3-Bond J-Couplings in Entire Polyalanine α-Helices. A Density Functional Theory Study. J Phys Chem B 2007; 111:2398-403. [PMID: 17295533 DOI: 10.1021/jp064706c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present the first trans-H-bond 13C-15N 3-bond J couplings calculated from entire neutral and protonated alpha-helical polyalanines. The neutral helices considered are those of the capped peptides, acetyl(Ala)NNH2, where N = 8, 16, 17, and 18, while the protonated peptides are the uncapped (Ala)17 protonated at three different positions. The calculated J values correlate well with O...H distances and somewhat less well with N...O distances, particularly if the terminal H-bonds are eliminated from the correlation. The J values calculated using the entire helix are about 6% lower in magnitude than those recently reported for H-bonding chains whose geometries were extracted from the same helices. Aqueous solvation favors protonation of the alpha-helix on the terminal COOH. Experimental measurements of the trans-H-bond 13C-15N 3-bond J couplings in acidic solution should be interpreted with this context.
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Affiliation(s)
- Pedro Salvador
- Department of Chemistry, City University of New York--Hunter College and the Graduate School, 695 Park Avenue, New York, New York 10021, USA
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Rai R, Aravinda S, Kanagarajadurai K, Raghothama S, Shamala N, Balaram P. Diproline Templates as Folding Nuclei in Designed Peptides. Conformational Analysis of Synthetic Peptide Helices Containing Amino Terminal Pro-Pro Segments. J Am Chem Soc 2006; 128:7916-28. [PMID: 16771506 DOI: 10.1021/ja060674v] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of N-terminal diproline segments in nucleating helical folding in designed peptides has been studied in two model sequences Piv-Pro-Pro-Aib-Leu-Aib-Phe-OMe (1) and Boc-Aib-Pro-Pro-Aib-Val-Ala-Phe-OMe (2). The structure of 1 in crystals, determined by X-ray diffraction, reveals a helical (alphaR) conformation for the segment residues 2 to 5, stabilized by one 4-->1 hydrogen bond and two 5-->1 interactions. The N-terminus residue, Pro(1) adopts a polyproline II (P(II)) conformation. NMR studies in three different solvent systems support a conformation similar to that observed in crystals. In the apolar solvent CDCl3, NOE data favor the population of both completely helical and partially unfolded structures. In the former, the Pro-Pro segment adopts an alphaR-alphaR conformation, whereas in the latter, a P(II)-alphaR structure is established. The conformational equilibrium shifts in favor of the P(II)-alphaR structure in solvents like methanol and DMSO. A significant population of the Pro(1)-Pro(2) cis conformer is also observed. The NMR results are consistent with the population of at least three conformational states about Pro-Pro segment: trans alphaR-alphaR, trans P(II)-alphaR and cis P(II)-alphaR. Of these, the two trans conformers are in rapid dynamic exchange on the NMR time scale, whereas the interconversion between cis and trans form is slow. Similar results are obtained with peptide 2. Analysis of 462 diproline segments in protein crystal structures reveals 25 examples of the alphaR-alphaR conformation followed by a helix. Modeling and energy minimization studies suggest that both P(II)-alphaR and alphaR-alphaR conformations have very similar energies in the model hexapeptide 1.
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Affiliation(s)
- Rajkishor Rai
- Molecular Biophysics Unit, Department of Physics and NMR Research Centre, Indian Institute of Science, Bangalore, 560 012, India
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Kennedy RJ, Walker SM, Kemp DS. Energetic characterization of short helical polyalanine peptides in water: analysis of 13C=O chemical shift data. J Am Chem Soc 2005; 127:16961-8. [PMID: 16316242 PMCID: PMC1560102 DOI: 10.1021/ja054645g] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Measured at 2 degrees C in water, NMR chemical shifts of (13)C=O labeled central alanine residues of peptides W-Lys(5)-(t)L(3)-Ala(n)-(t)L(3)-Lys(5)NH(2), n = 9, 11, 13, 15, 19 and W-Lys(5)-(t)L(3)-a-Ala(n)-A-Inp-(t)L(2)-Lys(5)NH(2) (a = D-Ala; (t)L = tert-leucine; Inp = 4-carboxypiperidine) are used to assign jt(L) and ct(L), the N- and C-terminal (t)L capping parameters and length-dependent values for w(Ala)(n), the alanine helical propensity for Ala(n) peptides. These parameters allow Lifson-Roig characterization of the stabilities of Ala(n)() helices in water. To facilitate chemical shift characterization, different (13)C/(12)C ratios are incorporated into specific Ala sites to code up to six residue sites per peptide. Large left/right chemical shift anisotropies are intrinsic to helical polyalanines, and a correcting L-R-based model is introduced. Capping parameters jt(L) = ct(L) lie in the range of 0.3 to 0.5; the (t)L residues are thus moderately helix-destabilizing. For helical conformations of lengths shorter than eight residues, assigned values for w(Ala) approach 1.0 but increase monotonically with length to a value of 1.59 for w(Ala)(19).
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Affiliation(s)
- Robert J Kennedy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, 02139, USA
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