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Gellen G, Klement E, Biwott K, Schlosser G, Kalló G, Csősz É, Medzihradszky KF, Bacso Z. Cross-Linking Mass Spectrometry on P-Glycoprotein. Int J Mol Sci 2023; 24:10627. [PMID: 37445813 DOI: 10.3390/ijms241310627] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
The ABC transporter P-glycoprotein (Pgp) has been found to be involved in multidrug resistance in tumor cells. Lipids and cholesterol have a pivotal role in Pgp's conformations; however, it is often difficult to investigate it with conventional structural biology techniques. Here, we applied robust approaches coupled with cross-linking mass spectrometry (XL-MS), where the natural lipid environment remains quasi-intact. Two experimental approaches were carried out using different cross-linkers (i) on living cells, followed by membrane preparation and immunoprecipitation enrichment of Pgp, and (ii) on-bead, subsequent to membrane preparation and immunoprecipitation. Pgp-containing complexes were enriched employing extracellular monoclonal anti-Pgp antibodies on magnetic beads, followed by on-bead enzymatic digestion. The LC-MS/MS results revealed mono-links on Pgp's solvent-accessible residues, while intraprotein cross-links confirmed a complex interplay between extracellular, transmembrane, and intracellular segments of the protein, of which several have been reported to be connected to cholesterol. Harnessing the MS results and those of molecular docking, we suggest an epitope for the 15D3 cholesterol-dependent mouse monoclonal antibody. Additionally, enriched neighbors of Pgp prove the strong connection of Pgp to the cytoskeleton and other cholesterol-regulated proteins. These findings suggest that XL-MS may be utilized for protein structure and network analyses in such convoluted systems as membrane proteins.
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Affiliation(s)
- Gabriella Gellen
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, H-1117 Budapest, Hungary
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | - Eva Klement
- Single Cell Omics Advanced Core Facility, HCEMM, H-6728 Szeged, Hungary
- Laboratory of Proteomics Research, BRC, H-6726 Szeged, Hungary
| | - Kipchumba Biwott
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | - Gitta Schlosser
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Gergő Kalló
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | - Éva Csősz
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | | | - Zsolt Bacso
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Faculty of Pharmacology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
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2
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Bhalodi EH, Patel KN, Bedekar AV. Synthesis and resolution of 2-amino-5-aza[6]helicene. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.132761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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3
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Huseman ED, Byl JAW, Chapp SM, Schley ND, Osheroff N, Townsend SD. Synthesis and Cytotoxic Evaluation of Arimetamycin A and Its Daunorubicin and Doxorubicin Hybrids. ACS Cent Sci 2021; 7:1327-1337. [PMID: 34471677 PMCID: PMC8393218 DOI: 10.1021/acscentsci.1c00040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Indexed: 05/10/2023]
Abstract
The arimetamycin A glycan governs the compound's cytotoxicity (IC50). To study this branched, deoxy-amino disaccharide, we designed and synthesized a modified acyl donor that underwent glycosylation with three anthracycline aglycones: steffimycinone, daunorubicinone, and doxorubicinone. The result of the approach was a synthesis of arimetamycin A and two novel hybrid anthracyclines. Each molecule exhibited enhanced cytotoxicity in comparison to the parent anthracyclines, steffimycin B, daunorubicin, and doxorubicin. An orienting mechanistic evaluation revealed that the daunorubicin hybrid inhibits the ability of human topoisomerase IIα to relax negatively and positively supercoiled DNA.
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Affiliation(s)
- Eric D. Huseman
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jo Ann W. Byl
- Department of Biochemistry and Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, Tennessee 37215, United States
| | - Scott M. Chapp
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Nathan D. Schley
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Neil Osheroff
- Department of Biochemistry and Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, Tennessee 37215, United States
- VA
Tennessee Valley Healthcare System, Nashville, Tennessee 37212, United States
| | - Steven D. Townsend
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
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4
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May HC, Yu JJ, Shrihari S, Seshu J, Klose KE, Cap AP, Chambers JP, Guentzel MN, Arulanandam BP. Thioredoxin Modulates Cell Surface Hydrophobicity in Acinetobacter baumannii. Front Microbiol 2019; 10:2849. [PMID: 31921031 PMCID: PMC6927278 DOI: 10.3389/fmicb.2019.02849] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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: 09/03/2019] [Accepted: 11/25/2019] [Indexed: 12/04/2022] Open
Abstract
Acinetobacter baumannii, a Gram-negative coccobacillus, has become a prevalent nosocomial health threat affecting the majority of hospitals both in the U.S. and around the globe. Microbial cell surface hydrophobicity (CSH) has previously been correlated with virulence, uptake by immune cells, and attachment to epithelial cells. A mutant strain of A. baumannii (ΔtrxA) lacking the redox protein thioredoxin A was found to be more hydrophobic than its wild type (WT) and complemented counterparts, as measured by both Microbial Adhesion to Hydrocarbon (MATH) and salt aggregation. The hydrophobicity of the mutant could be abrogated through treatment with sodium cyanoborohydride (SCBH). This modulation correlated with reduction of disulfide bonds, as SCBH was able to reduce 5,5′-dithio-bis-[2-nitrobenzoic acid] and treatment with the known disulfide reducer, β-mercaptoethanol, also decreased ΔtrxA CSH. Additionally, the ΔtrxA mutant was more readily taken up than WT by J774 macrophages and this differential uptake could be abrogated though SCBH treatment. When partitioned into aqueous and hydrophobic phases, ΔtrxA recovered from the hydrophobic partition was phagocytosed more readily than from the aqueous phase further supporting the contribution of CSH to A. baumannii uptake by phagocytes. A second Gram-negative bacterium, Francisella novicida, also showed the association of TrxA deficiency (FnΔtrxA) with increased hydrophobicity and uptake by J774 cells. We previously have demonstrated that modification of the type IV pilus system (T4P) was associated with the A. baumannii ΔtrxA phenotype, and the Francisella FnΔtrxA mutant also was found to have a marked T4P deficiency. Interestingly, a F. novicida mutant lacking pilT also showed increased hydrophobicity over FnWT. Collective evidence presented in this study suggests that Gram-negative bacterial thioredoxin mediates CSH through multiple mechanisms including disulfide-bond reduction and T4P modulation.
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Affiliation(s)
- Holly C May
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - Jieh-Juen Yu
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - Swathi Shrihari
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - Janakiram Seshu
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - Karl E Klose
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - Andrew P Cap
- Acute Combat Casualty Care Research Division, U.S. Army Institute for of Surgical Research, JBSA-Fort Sam Houston, San Antonio, TX, United States
| | - James P Chambers
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - M Neal Guentzel
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - Bernard P Arulanandam
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
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5
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Abstract
AbstractFormaldehyde is a biological electrophile produced via processes including enzymatic demethylation. Despite its apparent simplicity, the reactions of formaldehyde with even basic biological components are incompletely defined. Here we report NMR-based studies on the reactions of formaldehyde with common proteinogenic and other nucleophilic amino acids. The results reveal formaldehyde reacts at different rates, forming hydroxymethylated, cyclised, cross-linked, or disproportionated products of varying stabilities. Of the tested common amino acids, cysteine reacts most efficiently, forming a stable thiazolidine. The reaction with lysine is less efficient; low levels of an Nε-methylated product are observed, raising the possibility of non-enzymatic lysine methylation by formaldehyde. Reactions with formaldehyde are faster than reactions with other tested biological carbonyl compounds, and the adducts are also more stable. The results reveal reactions of formaldehyde with amino acids, and by extension peptides and proteins, have potential roles in healthy and diseased biology, as well as in evolution.
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6
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Liu Z, Zhou Y, Liu J, Chen J, Heck AJ, Wang F. Reductive methylation labeling, from quantitative to structural proteomics. Trends Analyt Chem 2019; 118:771-8. [DOI: 10.1016/j.trac.2019.07.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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7
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Abstract
Although thousands of intact proteins have been feasibly identified in recent years, global quantification of intact proteins is still challenging. Herein, we develop a high-throughput strategy for global intact protein quantification based on chemical isotope labeling. The isotope incorporation efficiency is as high as 99.2% for complex intact protein samples extracted from HeLa cells. Further, the pTop 2.0 software is developed for automated quantification of intact proteoforms in a high-throughput manner. The high quantification accuracy and reproducibility of this strategy have been demonstrated for both standard and complex cellular protein samples. A total of 2283 intact proteoforms originated from 660 protein accessions are successfully quantified under anaerobic and aerobic conditions and the differentially expressed proteins are observed to be involved in the important biological processes such as stress response.
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Affiliation(s)
- Zheyi Liu
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian , 116023 , China
| | - Ruimin Wang
- Institute of Computing Technology , Chinese Academy of Sciences , Beijing , 100190 , China
| | - Jing Liu
- College of Pharmacy , Dalian Medical University , Dalian , 116044 , China
| | - Ruixiang Sun
- Institute of Computing Technology , Chinese Academy of Sciences , Beijing , 100190 , China
| | - Fangjun Wang
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian , 116023 , China
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8
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Hurtado Silva M, Berry IJ, Strange N, Djordjevic SP, Padula MP. Terminomics Methodologies and the Completeness of Reductive Dimethylation: A Meta-Analysis of Publicly Available Datasets. Proteomes 2019; 7:proteomes7020011. [PMID: 30934878 PMCID: PMC6631386 DOI: 10.3390/proteomes7020011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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: 01/16/2019] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 12/30/2022] Open
Abstract
Methods for analyzing the terminal sequences of proteins have been refined over the previous decade; however, few studies have evaluated the quality of the data that have been produced from those methodologies. While performing global N-terminal labelling on bacteria, we observed that the labelling was not complete and investigated whether this was a common occurrence. We assessed the completeness of labelling in a selection of existing, publicly available N-terminomics datasets and empirically determined that amine-based labelling chemistry does not achieve complete labelling and potentially has issues with labelling amine groups at sequence-specific residues. This finding led us to conduct a thorough review of the historical literature that showed that this is not an unexpected finding, with numerous publications reporting incomplete labelling. These findings have implications for the quantitation of N-terminal peptides and the biological interpretations of these data.
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Affiliation(s)
- Mariella Hurtado Silva
- Proteomics Core Facility and School of Life Sciences, Faculty of Science, University of Technology Sydney, Broadway NSW 2007, Australia.
| | - Iain J Berry
- Proteomics Core Facility and School of Life Sciences, Faculty of Science, University of Technology Sydney, Broadway NSW 2007, Australia.
- The ithree Institute, Faculty of Science, University of Technology Sydney, Broadway NSW 2007, Australia.
| | - Natalie Strange
- Proteomics Core Facility and School of Life Sciences, Faculty of Science, University of Technology Sydney, Broadway NSW 2007, Australia.
| | - Steven P Djordjevic
- The ithree Institute, Faculty of Science, University of Technology Sydney, Broadway NSW 2007, Australia.
| | - Matthew P Padula
- Proteomics Core Facility and School of Life Sciences, Faculty of Science, University of Technology Sydney, Broadway NSW 2007, Australia.
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9
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Nuriel T, Whitehouse J, Ma Y, Mercer EJ, Brown N, Gross SS. ANSID: A Solid-Phase Proteomic Approach for Identification and Relative Quantification of Aromatic Nitration Sites. Front Chem 2016; 3:70. [PMID: 26779476 PMCID: PMC4703760 DOI: 10.3389/fchem.2015.00070] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/11/2015] [Indexed: 12/21/2022] Open
Abstract
Nitration of tyrosine and other aromatic amino acid residues in proteins occurs in the setting of inflammatory, neurodegenerative, and cardiovascular diseases—importantly, this modification has been implicated in the pathogenesis of diverse diseases and the physiological process of aging. To understand the biological consequences of aromatic nitration in both health and disease, it is critical to molecularly identify the proteins that undergo nitration, specify their cognate modification sites and quantify their extent of nitration. To date, unbiased identification of nitrated proteins has often involved painstaking 2D-gel electrophoresis followed by Western Blotting with an anti-nitrotyrosine antibody for detection. Apart from being relatively slow and laborious, this method suffers from limited coverage, the potential for false-positive identifications, and failure to reveal specific amino acid modification sites. To overcome these shortcomings, we have developed a solid-phase, chemical-capture approach for unbiased and high-throughput discovery of nitrotyrosine and nitrotryptophan sites in proteins. Utilizing this method, we have successfully identified several endogenously nitrated proteins in rat brain and a total of 244 nitrated peptides from 145 proteins following in vitro exposure of rat brain homogenates to the nitrating agent peroxynitrite (1 mM). As expected, Tyr residues constituted the great majority of peroxynitrite-mediated protein nitration sites; however, we were surprised to discover several brain proteins that contain nitrated Trp residues. By incorporating a stable-isotope labeling step, this new Aromatic Nitration Site IDentification (ANSID) method was also adapted for relative quantification of nitration site abundances in proteins. Application of the ANSID method offers great potential to advance our understanding of the role of protein nitration in disease pathogenesis and normal physiology.
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Affiliation(s)
- Tal Nuriel
- Department of Pharmacology, Weill Cornell Medical CollegeNew York, NY, USA; Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical CollegeNew York, NY, USA
| | - Julia Whitehouse
- Department of Pharmacology, Weill Cornell Medical College New York, NY, USA
| | - Yuliang Ma
- Department of Pharmacology, Weill Cornell Medical College New York, NY, USA
| | - Emily J Mercer
- Department of Pharmacology, Weill Cornell Medical CollegeNew York, NY, USA; Department of Surgery, Weill Cornell Medical CollegeNew York, NY, USA
| | - Neil Brown
- Department of Pharmacology, Weill Cornell Medical College New York, NY, USA
| | - Steven S Gross
- Department of Pharmacology, Weill Cornell Medical College New York, NY, USA
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10
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She YM, Rosu-Myles M, Walrond L, Cyr TD. Quantification of protein isoforms in mesenchymal stem cells by reductive dimethylation of lysines in intact proteins. Proteomics 2012; 12:369-79. [PMID: 22144135 PMCID: PMC3440571 DOI: 10.1002/pmic.201100308] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [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: 06/10/2011] [Revised: 10/11/2011] [Accepted: 11/02/2011] [Indexed: 11/05/2022]
Abstract
Mass spectrometry (MS)-based quantification of highly homologous proteins in complex samples has proven difficult due to subtle sequence variations and the wide dynamic range of protein isoforms present. Herein, we report the use of reductive dimethylation on intact proteins to quantitatively compare protein isoform expression in the nucleus and cytoplasm of mesenchymal stem cells (MSC) and normal stroma. By coupling fixed-charge MS/MS scanning, high-resolution UPLC FT-MS data-dependent acquisition and MASCOT-based data mining, hydrogen/deuterium-labeled dimethyl-lysine peptides were simultaneously captured allowing the accurate comparison of 123 protein isoforms in parallel LC MS/MS runs. Thirty-four isoforms were identified that had expression levels specific to MSC. Where possible, proteomic analyses were verified by Western blotting and were demonstrated to be divergent from the level of gene transcription detected for certain proteins. Our analysis provides a protein isoform signature specific to MSC and demonstrates the suitability of dimethyl-lysine labeling on intact proteins for quantifying highly homologous proteins on a proteome-wide scale.
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Affiliation(s)
- Yi-Min She
- Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, Ontario, Canada
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11
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Barrios-Llerena ME, Pritchard JC, Kerr LE, Le Bihan T. The use of a novel quantitation strategy based on Reductive Isotopic Di-Ethylation (RIDE) to evaluate the effect of glufosinate on the unicellular algae Ostreococcus tauri. J Proteomics 2011; 74:2798-809. [DOI: 10.1016/j.jprot.2011.06.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/19/2011] [Indexed: 11/26/2022]
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12
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Kleifeld O, Doucet A, Prudova A, auf dem Keller U, Gioia M, Kizhakkedathu JN, Overall CM. Identifying and quantifying proteolytic events and the natural N terminome by terminal amine isotopic labeling of substrates. Nat Protoc 2011; 6:1578-611. [PMID: 21959240 DOI: 10.1038/nprot.2011.382] [Citation(s) in RCA: 236] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Analysis of the sequence and nature of protein N termini has many applications. Defining the termini of proteins for proteome annotation in the Human Proteome Project is of increasing importance. Terminomics analysis of protease cleavage sites in degradomics for substrate discovery is a key new application. Here we describe the step-by-step procedures for performing terminal amine isotopic labeling of substrates (TAILS), a 2- to 3-d (depending on method of labeling) high-throughput method to identify and distinguish protease-generated neo-N termini from mature protein N termini with all natural modifications with high confidence. TAILS uses negative selection to enrich for all N-terminal peptides and uses primary amine labeling-based quantification as the discriminating factor. Labeling is versatile and suited to many applications, including biochemical and cell culture analyses in vitro; in vivo analyses using tissue samples from animal and human sources can also be readily performed. At the protein level, N-terminal and lysine amines are blocked by dimethylation (formaldehyde/sodium cyanoborohydride) and isotopically labeled by incorporating heavy and light dimethylation reagents or stable isotope labeling with amino acids in cell culture labels. Alternatively, easy multiplex sample analysis can be achieved using amine blocking and labeling with isobaric tags for relative and absolute quantification, also known as iTRAQ. After tryptic digestion, N-terminal peptide separation is achieved using a high-molecular-weight dendritic polyglycerol aldehyde polymer that binds internal tryptic and C-terminal peptides that now have N-terminal alpha amines. The unbound naturally blocked (acetylation, cyclization, methylation and so on) or labeled mature N-terminal and neo-N-terminal peptides are recovered by ultrafiltration and analyzed by tandem mass spectrometry (MS/MS). Hierarchical substrate winnowing discriminates substrates from the background proteolysis products and non-cleaved proteins by peptide isotope quantification and bioinformatics search criteria.
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13
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Affiliation(s)
- Shyamaprosad Goswami
- a Department of Chemistry , Bengal Engineering and Science University, Shibpur , Howrah , West Bengal , India
| | - Anita Hazra
- a Department of Chemistry , Bengal Engineering and Science University, Shibpur , Howrah , West Bengal , India
| | - Jia Hao Goh
- b X-Ray Crystallography Unit, School of Physics, Universiti Sains Malaysia , Penang , Malaysia
| | - Hoong-Kun Fun
- b X-Ray Crystallography Unit, School of Physics, Universiti Sains Malaysia , Penang , Malaysia
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14
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Abstract
The chemical modification of protein thiols by reduction and alkylation is common in the preparation of proteomic samples for analysis by mass spectrometry (MS). Modification at other functional groups has received less attention in MS-based proteomics. Amine modification (Lys, N-termini) by reductive dimethylation or by acylation (e.g., iTRAQ labeling) has recently gained some popularity in peptide-based approaches (bottom-up MS). Modification at acidic groups (Asp, Glu, C-termini) has been explored very minimally. Here, we describe a sequential labeling strategy that enables complete modification of thiols, amines, and acids on peptides or small intact proteins. This method includes (1) the reduction and alkylation of thiols, (2) the reductive dimethylation of amines, and (3) the amidation of acids with any of several amines. This chemical modification scheme offers several options both for the incorporation of stable isotopes for relative quantification and for improving peptides or proteins as MS analytes.
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Affiliation(s)
- Casey J Krusemark
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA.
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15
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Piret G, Desmet R, Diesis E, Drobecq H, Segers J, Rouanet C, Debrie AS, Boukherroub R, Locht C, Melnyk O. Chips from Chips: Application to the Study of Antibody Responses to Methylated Proteins. J Proteome Res 2010; 9:6467-78. [DOI: 10.1021/pr100707t] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Gaëlle Piret
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Rémi Desmet
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Eric Diesis
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Hervé Drobecq
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Jérome Segers
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Carine Rouanet
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Anne-Sophie Debrie
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Rabah Boukherroub
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Camille Locht
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
| | - Oleg Melnyk
- Institut de Recherche Interdisciplinaire (IRI), CNRS USR 3078, Villeneuve d’Ascq Cédex, France, CNRS UMR 8161, France, Institut Pasteur de Lille, Lille, France, IFR 142 Molecular and Cellular Medicine, Lille, France, INSERM U1019, Center for Infection and Immunity, Lille, France, CNRS UMR 8204, Lille, France, and Univ Lille Nord de France, Lille, France
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16
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Prenant C, Cawthorne C, Fairclough M, Rothwell N, Boutin H. Radiolabeling with fluorine-18 of a protein, interleukin-1 receptor antagonist. Appl Radiat Isot 2010; 68:1721-7. [PMID: 20435481 DOI: 10.1016/j.apradiso.2010.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/26/2010] [Accepted: 04/01/2010] [Indexed: 11/23/2022]
Abstract
IL-1RA is a naturally occurring antagonist of the pro-inflammatory cytokine interleukin-1 (IL-1) with high therapeutic promise, but its pharmacokinetic remains poorly documented. In this report, we describe the radiolabeling of recombinant human interleukin-1 receptor antagonist (rhIL-1RA) with fluorine-18 to allow pharmacokinetic studies by positron emission tomography (PET). rhIL-1RA was labeled randomly by reductive alkylation of free amino groups (the epsilon-amino group of lysine residues or amino-terminal residues) using [(18)F]fluoroacetaldehyde under mild reaction conditions. Radiosyntheses used a remotely controlled experimental rig within 100min and the radiochemical yield was in the range 7.1-24.2% (decay corrected, based on seventeen syntheses). We showed that the produced [(18)F]fluoroethyl-rhIL-1ra retained binding specificity by conducting an assay on rat brain sections, allowing its pharmakokinetic study using PET.
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17
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Desmet R, Diesis E, Drobecq H, Rouanet C, Chemlal K, Debrie AS, Hougardy JM, Mascart F, Locht C, Melnyk O. In situ chemical modification of peptide microarrays: application to the study of the antibody responses to methylated antigens. Methods Mol Biol 2010; 669:135-45. [PMID: 20857363 DOI: 10.1007/978-1-60761-845-4_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Peptide microarrays are useful tools for characterizing the humoral response against methylated antigens. They are usually prepared by printing unmodified and methylated peptides on substrates such as functionalized microscope glass slides. The preferential capture of antibodies by methylated peptides suggests the specific recognition of methylated epitopes. However, unmodified peptide epitopes can be masked due to their interaction with the substrate. The accessibility of unmodified peptides and thus the specificity of the recognition of methylated peptide epitopes can be probed using the in situ methylation procedure described here. Alternately, the in situ methylation of peptide microarrays allows probing the presence of antibodies directed toward methylated epitopes starting from easy-to-make and cost-effective unmodified peptide libraries. In situ methylation was performed using formaldehyde in the presence of sodium cyanoborohydride and nickel chloride. This chemical procedure converts lysine residues into mono- or dimethyl lysines.
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Affiliation(s)
- Rémi Desmet
- UMR 8161 CNRS-Université de Lille Nord de France, Lille, France
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18
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Adrover M, Vilanova B, Muñoz F, Donoso J. Unexpected isomeric equilibrium in pyridoxamine Schiff bases. Bioorg Chem 2008; 37:26-32. [PMID: 19091373 DOI: 10.1016/j.bioorg.2008.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 11/05/2008] [Accepted: 11/05/2008] [Indexed: 10/21/2022]
Abstract
Pyridoxamine is a vitamin B(6) derivative involved in biological reactions such as transamination, and can also act as inhibitor in protein glycation. In both cases, it has been reported that Schiff base formation between pyridoxamine and carbonyl compounds is the main step. Nevertheless, few studies on the Schiff base formation have been reported to date. In this work, we conduct a comparative study of the reaction of pyridoxamine and 4-picolylamin (a pyridoxamine analog) with various carbonyl compounds including propanal, formaldehyde and pyruvic acid. Based on the results, 4-picolylamin forms a Schiff base as end-product of its reactions with propanal and pyruvic acid, but a carbinolamine with formaldehyde. On the other hand, pyridoxamine forms a Schiff base with the three reagents, but the end-product is in equilibrium with its hemiaminal form, which results from the attack of the phenolate ion of the pyridine ring on the imine carbon. This isomeric equilibrium should be considered in studying reactions involving amine derivatives of vitamin B(6).
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Affiliation(s)
- Miquel Adrover
- Institut Universitari d'Investigació en Ciències de la Salut, Departament de Química, Universitat de les Illes Balears, Palma de Mallorca, Spain
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19
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Abstract
In the present work, reductive alkylation of proteins and peptides with glutaraldehyde (reductive glutaraldehydation) is reported. The reaction is highly efficient and forms piperidine at the N-terminus as well as the side chain of lysine residues. The complete modification of protein amines was achieved by reductive glutaraldehydation in solution or in the gel in less than 15 min. The glutaraldehyde-modified peptides display an enhanced intensity in mass spectra and show higher retention time in reversed phase chromatography in comparison to unmodified peptides. Fragmentation of glutaraldehyde-modified proteins and peptides generates a1 fragment ions with enhanced intensity in MS/MS spectra. Thus, a method based on reductive glutaraldehydation and LC-MS/MS analysis has been developed to determine the N-terminal residue of proteins with free N-termini.
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Affiliation(s)
- Allison Russo
- The Proteomics Resource Center, Rockefeller University, New York, NY 10065, USA
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20
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Adrover M, Vilanova B, Frau J, Muñoz F, Donoso J. The pyridoxamine action on Amadori compounds: A reexamination of its scavenging capacity and chelating effect. Bioorg Med Chem 2008; 16:5557-69. [DOI: 10.1016/j.bmc.2008.04.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 03/26/2008] [Accepted: 04/01/2008] [Indexed: 10/22/2022]
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21
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Abstract
A sequential reaction methodology is employed for the complete derivatization of protein thiols, amines, and acids in high purity under denaturing conditions. Following standard thiol alkylation, protein amines are modified via reductive methylation with formaldehyde and pyridine-borane. Protein acids are subsequently amidated under buffered conditions in DMSO using the coupling reagent (7-azabenzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate. The generality of the approach is demonstrated with four proteins and with several amines yielding near-quantitative transformations as characterized by high-resolution Fourier transform mass spectrometry. The developed approach has numerous implications for protein characterization and general protein chemistry. Applications in mass spectrometry (MS) based proteomics of intact proteins (top-down MS) are explored, including the addition of stable isotopes for relative quantitation and protein identification through functional group counting. The methodology can be used for altering the physical and chemical properties of proteins, as demonstrated with amidation to modify protein isoelectric point and through derivatization with quaternary amines. Additionally, the chemistry has applications in the semisynthesis of monodisperse polymers based on protein scaffolds. We prepare proteins modified with azides and alkynes to enable further functionalization via copper(I)-catalyzed 1,3-dipolar Huisgen cycloaddition ("click") chemistry.
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22
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Stewart BJ, Doorn JA, Petersen DR. Residue-specific adduction of tubulin by 4-hydroxynonenal and 4-oxononenal causes cross-linking and inhibits polymerization. Chem Res Toxicol 2007; 20:1111-9. [PMID: 17630713 DOI: 10.1021/tx700106v] [Citation(s) in RCA: 65] [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: 11/29/2022]
Abstract
The modification of proteins by lipid aldehydes produced in cells undergoing oxidative stress has been proposed as an important event that contributes to the pathology of numerous diseases. In this context, the alpha,beta-unsaturated aldehydes 4-hydroxynonenal (4-HNE) and 4-oxononenal (4-ONE) generated during membrane lipid peroxidation have been shown to adduct and inactivate numerous proteins. We report here that purified bovine brain tubulin modified with physiologically relevant concentrations of 4-HNE or 4-ONE results in significant protein cross-linking and marked inhibition of the functional capacity of tubulin polymerization. Comparative analysis demonstrated that 4-ONE is a much more potent cross-linker and inhibitor of tubulin assembly than 4-HNE. Additional experiments revealed the unique property of 4-ONE, initiation of depolymerization of intact microtubules. LC-MS/MS analysis demonstrated that Cys 347alpha, Cys 376alpha, and Cys 303beta are consistently modified by 4-HNE. The identification of target residues within tubulin modified by 4-ONE was not successful, and this was attributed to the marked tubulin cross-linking that occurred immediately after addition of 4-ONE. The modification of Lys residues by reductive propylation demonstrated that the majority of 4-HNE and 4-ONE adducts involve Lys residues, suggesting that tubulin cross-links are Lys-dependent. Taken together, these data suggest a mechanistic basis for the impairment of tubulin function by 4-HNE and 4-ONE produced as a consequence of diseases associated with chronic oxidative stress.
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Affiliation(s)
- Benjamin J Stewart
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver and Health Sciences Center, Denver, CO 80262,USA
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23
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Rauert W, Eddine AN, Kaufmann SHE, Weiss MS, Janowski R. Reductive methylation to improve crystallization of the putative oxidoreductase Rv0765c from Mycobacterium tuberculosis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:507-11. [PMID: 17554174 PMCID: PMC2335070 DOI: 10.1107/s1744309107022506] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 05/07/2007] [Indexed: 11/10/2022]
Abstract
Rv0765c from Mycobacterium tuberculosis was cloned and heterologously expressed in Escherichia coli. It was purified using affinity and size-exclusion chromatographic techniques and crystallized. The native protein crystallized in a hexagonal crystal form which diffracted to 7 A resolution. In an attempt to improve the quality of the Rv0765c crystals, the protein was modified by reductive methylation using dimethylaminoborane and formaldehyde. The modified protein crystallized under different conditions in a tetragonal crystal form, from which diffraction data could be collected to a resolution of 3.2 A. In both crystal forms of Rv0765c, the asymmetric unit contained two copies of the protein molecule.
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Affiliation(s)
- Wilko Rauert
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Ali Nasser Eddine
- Max-Planck-Institute for Infection Biology, Schumannstrasse 21/22, D-10117 Berlin, Germany
| | - Stefan H. E. Kaufmann
- Max-Planck-Institute for Infection Biology, Schumannstrasse 21/22, D-10117 Berlin, Germany
| | - Manfred S. Weiss
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Robert Janowski
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
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24
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Huang Z, Du J, Zhao Y, Li Y. Synthesis of Site-Specifically Dimethylated and Trimethylated Peptides Derived from Histone H3 N-Terminal Tail. Int J Pept Res Ther 2006; 12:187-93. [DOI: 10.1007/s10989-005-9006-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Ashfield JT, Meyers T, Lowne D, Varley PG, Arnold JR, Tan P, Yang JC, Czaplewski LG, Dudgeon T, Fisher J. Chemical modification of a variant of human MIP-1alpha; implications for dimer structure. Protein Sci 2000; 9:2047-53. [PMID: 11106181 PMCID: PMC2144463 DOI: 10.1110/ps.9.10.2047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A sequence variant of human MIP-1alpha, in which Asp26 has been replaced by Al alpha, has been chemically modified by the addition of 13C-labeled methyl groups at each of the lysine residues and the N-terminus. The sites of methylation have been verified by a combination of MALDI-TOF mass spectrometric experiments and tryptic digestion followed by N-terminal mapping. The effect of the modification on the structure and activity of the protein have been determined by analytical ultra-centrifugation, 13C NMR spectroscopy and receptor binding studies. The results of these experiments suggest that huMIP-alpha D26A (BB10010), when present as a dimer, adopts a globular structure, like MCP-3, rather than the elongated or cylindrical structure determined for dimers of huMIP-1beta and RANTES.
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Affiliation(s)
- J T Ashfield
- School of Chemistry, University of Leeds, United Kingdom
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26
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Abstract
Deoxyhypusine (Nepsilon-(4-aminobutyl)lysine) is the key intermediate in the posttranslational synthesis of the unique amino acid, hypusine (Nepsilon-(4-amino-2-hydroxybutyl)lysine). Deoxyhypusine synthase catalyzes the formation of deoxyhypusine by conjugation of the butylamine moiety of spermidine to the epsilon-amino group of one specific lysine residue of the eukaryotic translation initiation factor 5A (eIF-5A) precursor protein. However, in the absence of the eIF-5A precursor, catalysis involves only the NAD-dependent cleavage of spermidine to generate 1,3-diaminopropane and a putative 4-carbon amine intermediate that gives rise to Delta1-pyrroline. We have obtained evidence for a covalent enzyme-substrate intermediate that accumulates in the absence of the eIF-5A precursor. Incubation of human recombinant enzyme with [1, 8-3H]spermidine and NAD, followed by reduction with NaBH3CN, resulted in specific radiolabeling of the enzyme. The radioactive component in the reduced enzyme intermediate was identified as deoxyhypusine and was shown to occur at a single locus. The fact that labeled deoxyhypusine was found after treatment with a reducing agent suggests an intermediate with the butylamine moiety derived from spermidine attached through an imine linkage to the epsilon-amino group of a specific lysine residue of the enzyme. This residue has been identified as lysine 329. Separate experiments showing efficient transfer of labeled butylamine moiety from enzyme intermediate to eIF-5A precursor strongly support a reaction mechanism involving an imine intermediate.
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Affiliation(s)
- E C Wolff
- Oral and Pharyngeal Cancer Branch, NIDR, National Institutes of Health, Bethesda, Maryland 20892-4340, USA
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27
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28
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Abstract
Reductive methylation of myosin-S1 converts 97% of lysine residues in native myosin-S1 to dimethyllysine without detectable modification of other amino acid side chains. RM-S1 is catalytically active, although the rate and equilibrium constants of many of the steps of the actomyosin ATP hydrolysis mechanism have been altered. The steady-state rate of MgATP hydrolysis by modified myosin-S1 (RM-S1) is increased 4-5-fold in the absence of actin. However, the maximum steady-state rate of RM-S1 at saturating actin, 0.59 s-1, is less than one-tenth that observed for the unmodified protein, 7.4 s-1 (5 mM MOPS, 2 mM MgCl2, pH 7, 20 degrees C). Under single-turnover conditions [S1] > [ATP], the observed rate of ATP hydrolysis by RM-S1 is fit by a single exponential that is no more than twice the steady-state rate, which indicates that the bond splitting state is at least partially rate limiting for RM-S1. Although a small decrease in intrinsic tryptophan fluorescence is observed upon ATP binding to RM-acto-S1, the large and rapid fluorescence enhancement produced by aza-ATP binding to RM-acto-S1 is nearly normal. ATP binds and dissociates modified RM-S1 from actin with a second-order rate constant that is more than twice that observed for control S1. The changes in the kinetic mechanism produced by reductive methylation of lysine are qualitatively and quantitatively similar to the changes that are induced by either SH1 modification or substrate analogues such as GTP.
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Affiliation(s)
- H D White
- Department of Biochemistry, East Virginia Medical School, Norfolk 23501
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29
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Rypniewski WR, Holden HM, Rayment I. Structural consequences of reductive methylation of lysine residues in hen egg white lysozyme: an X-ray analysis at 1.8-A resolution. Biochemistry 1993; 32:9851-8. [PMID: 8373783 DOI: 10.1021/bi00088a041] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.5] [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: 01/30/2023]
Abstract
Chemical modification of proteins has been and continues to be an important biochemical tool for the study of protein structure and function. One such type of approach has been the reductive methylation of lysine residues. In order to address the consequences of such methylation on the crystallization and structural properties of a protein, the three-dimensional structure of hen egg white lysozyme in which all lysine residues have been alkylated has been determined and refined to a nominal resolution of 1.8 A and a crystallographic R factor of 17.3%. Crystals used in the investigation were grown from 1.5-1.8 M MgSO4 and 50 mM Tris at pH 8.0 and belonged to the space group P2(1)2(1)2(1) with unit cell dimensions of a = 30.6 A, b = 56.3 A, c = 73.2 A, and one molecule per asymmetric unit. It was not possible to grow crystals of the modified lysozyme under the conditions normally employed for the hen egg white protein. Overall, the three-dimensional structures of the native lysozyme and the modified protein are very similar with only two surface loops differing to any significant extent. Specifically, the positions of the alpha-carbons for these two forms of the protein, excluding the surface loops, superimpose with a root-mean-square value of 0.40 A. The magnitude of the structural changes observed between the modified an unmodified forms of lysozyme is similar to that seen when an identical protein structure is solved in two different crystalline lattices.(ABSTRACT TRUNCATED AT 250 WORDS)
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30
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Mullersman JE, Preston JF. Amatoxins bearing amino and carboxyl groups prepared by selective alteration of the aldehyde generated by periodate oxidation of methylated alpha-amanitin. Int J Pept Protein Res 1991; 37:544-51. [PMID: 1655668 DOI: 10.1111/j.1399-3011.1991.tb00773.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Amatoxins are cyclic peptides which can be purified from the carpophores of various mushroom species. Since they were first recognized as potent inhibitors of the nuclear RNA polymerases of most eukaryotes these peptides have served as important tools in the study of transcription. The presence of unusual amino acid residues in these peptides has provided opportunities to attempt a variety of semisynthetic modifications. We describe several new amatoxin derivatives that were prepared by selective modification of an aldehyde group which can be generated by periodate oxidation of 6'-O-methyl-alpha-amanitin. The derivatives which resulted from sodium cyanoborohydride-mediated coupling to the toxin of ammonia, glycine, and L-proline exhibited Ki values for calf thymus RNA polymerase II of 1.7 x 10(-7) M, 2.5 x 10(-7) M and 7.0 x 10(-6) M, respectively. Treatment of the aldehyde with sodium chlorite or hydroxylamine-O-sulfonic acid converted the amanitin aldehyde to the corresponding carboxyl or nitrile compounds with Ki values of 1.0 x 10(-7) M and 3.0 x 10(-9) M, respectively. Difficulties which were encountered in the preparation of these derivatives are discussed relative to peculiarities in the chemical behavior of the amanitin aldehyde.
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Affiliation(s)
- J E Mullersman
- Department of Microbiology and Cell Science, University of Florida, Gainesville
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31
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Affiliation(s)
- H D Heck
- Department of Biochemical Toxicology and Pathobiology, Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina
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32
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Abstract
Ro 23-6457, (all-E)-3,7-dimethyl-9-[2-(trifluoromethyl)-6-(nonyloxy)phenyl]-2, 4,6,8- nonatetraenoic acid, and Ro 23-2895, (all-E)-9-[2-(nonyloxy)phenyl]-3,7-dimethyl-2,4,6,8-nonatetraen oic acid, are two novel retinoid analogs which exhibit antiinflammatory activity in both the developing and the established rat adjuvant arthritis models [8]. Here we investigated the effect of these two compounds on the production of arachidonic acid (AA) metabolites in two in vitro test systems [i.e., Ca2+ ionophore A23187 (I)-stimulated resident rat peritoneal macrophages (MO) and cytokine-stimulated human dermal fibroblasts (HDF)]. Both compounds, Ro 23-6457 and Ro 23-2895, significantly inhibited the release of 14C-AA metabolites and the production of LTB4, PGE2, and 6-keto-PGF1 alpha in I-stimulated MO, at concentrations of 1-33 microM. Both compounds also inhibited the production of PGE2 in HDF stimulated by either rhuIL-1 alpha or huTNF alpha at concentrations of 1 x 10(-5) to 1 x 10(-7) M. Ro 23-2895 was also a potent inhibitor of IL-1-induced collagenase production in rheumatoid synovial cells (IC50 approximately 1 to 2.5 x 10(-8) M). The inhibitory profile of these novel compounds in these cell systems is therefore similar to that of other known antiinflammatory retinoids (e.g., all-trans- and 13-cis-retinoic acid). Inhibitory effects such as those described here might in part contribute to the antiinflammatory activity of these compounds in vivo.
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Affiliation(s)
- C Fiedler-Nagy
- Department of Allergy and Inflammation, Hoffmann-La Roche Inc., Nutley, NJ 07110
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33
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Abstract
The effect of borohydride reducing reagents on monoclonal and polyclonal antibodies was examined by enzyme-linked immunosorbent assay (ELISA). Each antibody showed different stability characteristics to the reducing reagents. Sodium cyanoborohydride was at least five times milder toward immunological activity than sodium borohydride, however, sodium cyanoborohydride with a catalytic amount of metal ion (Zn2+ or Al3+) can be as harsh as sodium borohydride. Activated hydrophobic borohydrides, 9BBN-pyridine, did not have any advantages in respect to the stabilities of antibodies. Antibodies to be used for immunosorbent purification must be evaluated individually to determine whether their structure is stable to immobilization reagents and conditions prior to their linkage to the column support.
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Abstract
The use of chemical modification of proteins has increased exponentially during the past two decades. Today the many different uses of chemical modification include determination of relative reactivities of side chain groups, the quantitation of individual amino acids, development of affinity reagents, mechanism-based reagents for pharmaceutical uses, cross-linking reagents, special techniques for bioprostheses, blocking reagents for peptide synthesis, and reagents for specific cleavages of peptide bonds. Chemical modification should continue to be a primary tool in protein chemistry. It can supply information or products difficult or impossible to attain by the newer powerful technique of in vitro mutagenesis as well as serve as a supplementary procedure for the latter.
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35
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Strobel JL, Baynes JW, Thorpe SR. 125I-glycoconjugate labels for identifying sites of protein catabolism in vivo: effect of structure and chemistry of coupling to protein on label entrapment in cells after protein degradation. Arch Biochem Biophys 1985; 240:635-45. [PMID: 2411222 DOI: 10.1016/0003-9861(85)90071-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Residualizing radioactive labels are designed to remain entrapped within cells following degradation of a carrier protein, and have been used for identification of the tissue and cellular sites of plasma protein catabolism. In this study we describe a convenient synthesis and purification of a series of 125I-labeled glycoconjugates, and an evaluation of their efficiency of retention in liver following degradation of a model carrier protein, asialofetuin. Glycoconjugates were prepared in 65-90% yield by reductive amination of reducing sugars with aromatic amines using NaBH3CN. The products were purified in a single ion-exchange chromatographic step, and then labeled with 125I. The derivatives prepared were mono-and disubstituted lactitol-,cellobiitol-and glucitol-[125I]tyramine and lactitol-[125I]tyrosine. 125I-Glycoconjugates were coupled to asialofetuin using either cyanuric chloride or, for lactose-containing labels, by treatment with galactose oxidase followed by reductive amination with NaBH3CN. Attachment of labels by either procedure did not affect the normal rapid clearance of asialofetuin from the rat circulation nor its uptake and degradation in liver lysosomes. Leakage of 125I-labeled degradation products from cells was measured by following the kinetics of loss of whole-body radioactivity. We observed that degradation products from larger, disubstituted glycoconjugates were retained more efficiently than those from smaller and monosubstituted derivatives, and that glycoconjugates coupled to protein via reductive amination were retained in the body more efficiently than those coupled by cyanuric chloride. Overall, dilactitol-[125I]tyramine coupled to protein by reductive amination was entrapped most efficiently in liver.
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36
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Haas R, Rosenberry TL. Quantitative identification of N-terminal amino acids in proteins by radiolabeled reductive methylation and amino acid analysis: application to human erythrocyte acetylcholinesterase. Anal Biochem 1985; 148:154-62. [PMID: 4037298 DOI: 10.1016/0003-2697(85)90640-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A novel method of determining N-terminal amino acids in proteins is introduced. Reductive methylation of a protein with radiolabeled formaldehyde methylates both the alpha-amino group of the N-terminal amino acid and the epsilon-amino groups of Lys residues. The radiomethylated amino acids are stable to acid hydrolysis, and each of 16 possible hydrolysis-stable N-terminal amino acids can be identified by the unique elution positions of its N alpha-methyl and N alpha,N alpha-dimethyl derivatives with an appropriate amino acid analyzer elution schedule. The technique is at least as sensitive as other N-terminal amino acid determinations and, in addition, permits a quantitative evaluation of the number of N-terminal groups in a sample. Reductive methylation of bovine serum albumin revealed N-terminal Asp at a stoichiometry of 0.97 amino acid residue per polypeptide, while methylation of prolactin resulted in 0.86 residue of N-terminal Thr per polypeptide. Human erythrocyte acetylcholinesterase contained two N-terminal amino acids with stoichiometries of 0.66 Glu and 0.34 Arg per 70-kDa subunit. Identification of Glu as the principal N-terminus of acetylcholinesterase was confirmed by Edman sequencing.
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37
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Overton M, Hickman JA, Threadgill MD, Vaughan K, Gescher A. The generation of potentially toxic, reactive iminium ions from the oxidative metabolism of xenobiotic N-alkyl compounds. Biochem Pharmacol 1985; 34:2055-61. [PMID: 3924054 DOI: 10.1016/0006-2952(85)90394-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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38
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Walton DJ, Ison ER, Szarek WA. Synthesis of N-(1-deoxyhexitol-1-yl)amino acids, reference compounds for the nonenzymic glycosylation of proteins. Carbohydr Res 1984; 128:37-49. [PMID: 6733725 DOI: 10.1016/0008-6215(84)85082-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The N-(1-deoxy-D-mannitol-1-yl) and N-(1-deoxy-D-glucitol-1-yl) derivatives of L-valine, L-alanine, L-threonine, and L-leucine were prepared by reductive amination of D-mannose and D-glucose with the appropriate amino acids, in the presence of sodium cyanoborohydride. N epsilon-(1-Deoxy-D-mannitol-1-yl)- and N epsilon-(1-deoxy-D-glucitol-1-yl)-L-lysine were prepared by similar reactions of hexoses with N alpha-tert-butoxycarbonyl and N alpha-benzyloxycarbonyl-L-lysine, followed by removal of the protecting groups. The structures were confirmed by 1H-n.m.r. spectroscopy, which showed that each compound was completely free of its C-2 epimer. The synthetic compounds may be used as reference compounds for the identification of N-(1-deoxyhexitol-1-yl)amino acids formed when N-(1-deoxy-D-fructose-1-yl) groups of nonenzymically glycosylated proteins, of the hemoglobin A1c type, are reduced with sodium borohydride, and the protein is subjected to acid-catalyzed hydrolysis.
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Abstract
Pyridine borane has been reported as a superior reagent over a wide pH range, 5-9, for the reductive methylation of amino groups of proteins with formaldehyde [J. C. Cabacungan , A. I. Ahmed , and R. E. Feeney (1982) Anal. Biochem. 124, 272-278]. It has also been reported to reduce tryptophan to dihydrotryptophan and to inactivate lysozyme in trifluoroacetic acid [M. Kurata , Y. Kikugawa , T. Kuwae , I. Koyama , and T. Takagi (1980) Chem. Pharm . Bull 28, 2274-2275]. In the present study the specificity of pyridine borane for the two different modifications under different reaction conditions has been demonstrated, and extended to the application to the synthesis of protein containing reductively attached carbohydrates. In the acid reduction, pyridine borane selectively reduced all six tryptophans in lysozyme to dihydrotryptophan while all other amino acids remained intact. On similar treatment no cleavage of the carbohydrate moiety from chicken ovomucoid, and no losses of activity of ovomucoid or ribonuclease, two proteins devoid of tryptophan, were observed. Nearly complete methylation of the lysines of lysozyme, chicken ovomucoid, and ribonuclease was achieved with formaldehyde at pH 7.0 after 2 h at room temperature, with the retention of full activity of the protein without any destruction of tryptophan. The same chemistry was applied to covalently attach glucose and lactose to bovine serum albumin. Parameters, including pH, temperature, and methanol, that affect the reactions were investigated. Incremental additions of pyridine borane during the course of the reactions increased the rate of modification. The covalent attachment of sugar to the epsilon-amino group of lysine was demonstrated by the synthesis of N-alpha- acetylglucitollysine and comparison with acid hydrolysates of the bovine serum albumin-sugar derivatives.
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Hunter BK, Nicholls KM, Sanders JK. Formaldehyde metabolism by Escherichia coli. In vivo carbon, deuterium, and two-dimensional NMR observations of multiple detoxifying pathways. Biochemistry 1984; 23:508-14. [PMID: 6367820 DOI: 10.1021/bi00298a017] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
13C NMR has been used to demonstrate the metabolism of dilute solutions of labeled formaldehyde by Escherichia coli to methanol, formate, carbon dioxide, and several other unidentified metabolites which contain labeled CH2 groups. Aeration of bacterial suspensions within the spectrometer dramatically increased the rate of oxidation to formate and carbon dioxide. Deoxygenation with nitrogen gas virtually abolished all metabolism, as did the exposure of bacteria to very high formaldehyde concentrations. Deuterium NMR of whole cells in deuterium-depleted water further demonstrated the conversion of formaldehyde-d2 to methanol-d2, ruling out a formaldehyde dismutase as an important species. Two-dimensional proton-carbon chemical shift correlation was used to reveal the chemical shifts of the protons attached to 13C labels in metabolites. The results indicate that formaldehyde is efficiently detoxified by the bacterial cell through a route or routes which do not appear to involve tetrahydrofolate. This detoxification may be in competition with the lethal antibacterial processes associated with formaldehyde.
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Abstract
Formaldehyde release in aqueous solutions of noxythiolin (N-methyl-N'-hydroxymethyl thiourea) has been monitored by nuclear magnetic resonance (n.m.r.) spectroscopy. The results suggest that antibacterial activity in such solutions resides mainly in the free formaldehyde. N.m.r. spectroscopy also demonstrated slow C-N bond rotation in noxythiolin and N-methylthiourea, with delta G of ca 15 kcal mol-1 (63 kJ mol-1). N-Hydroxymethyl imidazole is marginally more effective than corresponding hydrated formaldehyde solutions, an effect which is attributed to more rapid turnover of unhydrated formaldehyde as detected by saturation transfer n.m.r. spectroscopy. These observations are combined with the known delivery of lethal iminium ions, R2N+ = CH2, by compounds of the form R2NCH2X (X = OH, NR2; R is alkyl) to suggest a single consistent explanation of the antibacterial properties of a wide range of masked formaldehyde compounds.
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Sherman G, Rosenberry TL, Sternlicht H. Identification of lysine residues essential for microtubule assembly. Demonstration of enhanced reactivity during reductive methylation. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32900-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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