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Li Z, Wang Q, Wang K, Zhang W, Ye M. An antibody-free enrichment approach enabled by reductive glutaraldehydation for monomethyllysine proteome analysis. Proteomics 2023; 23:e2100378. [PMID: 35532377 DOI: 10.1002/pmic.202100378] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/14/2022] [Accepted: 05/03/2022] [Indexed: 11/06/2022]
Abstract
Protein lysine monomethylation is an important post-translational modification participated in regulating many biological processes. There is growing interest in identifying these methylation events. However, the introduction of one methyl group on lysine residues has negligible effect on changing the physical and chemical properties of proteins or peptides, making enriching and identifying monomethylated lysine (Kme1) proteins or peptides extraordinarily challenging. In this study, we proposed an antibody-free chemical proteomics approach to capture Kme1 peptides from complex protein digest. By exploiting reductive glutaraldehydation, 5-aldehyde-pentanyl modified Kme1 residues and piperidine modified primary amines were generated at the same time. The peptides with aldehyde modified Kme1 residues were then enriched by solid-phase hydrazide chemistry. This chemical proteomics approach was validated by using several synthetic peptides. It was demonstrated that it can enrich and detect Kme1 peptide from peptide mixture containing 5000-fold more bovine serum albumin tryptic digest. Besides, we extended our approach to profile Kme1 using heavy methyl stable isotope labeling by amino acids in cell culture (hmSILAC) labeled Jurkat T cells and Hela cells. Totally, 29 Kme1 sites on 25 proteins were identified with high confidence and 11 Kme1 sites were identified in both two types cells. This is the first antibody-free chemical proteomics approach to enrich Kme1 peptides from complex protein digest, and it provides a potential avenue for the analysis of methylome.
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Affiliation(s)
- Zhouxian Li
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China.,Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (CAS), Dalian, China
| | - Qi Wang
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (CAS), Dalian, China
| | - Keyun Wang
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (CAS), Dalian, China
| | - Weibing Zhang
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Mingliang Ye
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (CAS), Dalian, China
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2
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Selective enrichment of N-terminal proline peptides via hydrazide chemistry for proteomics analysis. Anal Chim Acta 2020; 1142:48-55. [PMID: 33280703 DOI: 10.1016/j.aca.2020.10.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/17/2020] [Accepted: 10/20/2020] [Indexed: 11/20/2022]
Abstract
A challenge for shotgun proteomics is the identification of low abundance proteins, which is always hampered owing to the extreme complexity of protein digests and highly dynamic concentration range of proteins. To reduce the complexity of the peptide mixture, we developed a novel method to selectively enrich N-terminal proline peptides via hydrazide chemistry. This method consisted of ortho-phthalaldehyde (OPA) blocking of primary amines in peptides, reductive glutaraldehydation of N-terminal proline and solid phase hydrazide chemistry enrichment of aldehyde-modified N-terminal proline peptide. After enrichment, the number of detected peptides containing N-terminal proline increased from 1304 to 4039 and the ratio of N-terminal proline peptides jumped from 4.4% to 93.7%, showing good enrichment specificity towards N-terminal proline peptides. Besides, the ratio of identified peptides to proteins was decreased from 7.8 (29751/3811) to 1.5 (4347/2821), indicating that sample complexity was drastically reduced through this method. As a result, this novel approach for enriching N-terminal proline peptides is effective in identification of low abundance protein owing to the reduction of sample complexity.
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3
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Lycette BE, Glickman JW, Roth SJ, Cram AE, Kim TH, Krizanc D, Weir MP. N-Terminal Peptide Detection with Optimized Peptide-Spectrum Matching and Streamlined Sequence Libraries. J Proteome Res 2016; 15:2891-9. [PMID: 27498768 DOI: 10.1021/acs.jproteome.5b00996] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We identified tryptic peptides in yeast cell lysates that map to translation initiation sites downstream of the annotated start sites using the peptide-spectrum matching algorithms OMSSA and Mascot. To increase the accuracy of peptide-spectrum matching, both algorithms were run using several standardized parameter sets, and Mascot was run utilizing a, b, and y ions from collision-induced dissociation. A large fraction (22%) of the detected N-terminal peptides mapped to translation initiation downstream of the annotated initiation sites. Expression of several truncated proteins from downstream initiation in the same reading frame as the full-length protein (frame 1) was verified by western analysis. To facilitate analysis of the larger proteome of Drosophila, we created a streamlined sequence library from which all duplicated trypsin fragments had been removed. OMSSA assessment using this "stripped" library revealed 171 peptides that map to downstream translation initiation sites, 76% of which are in the same reading frame as the full-length annotated proteins, although some are in different reading frames creating new protein sequences not in the annotated proteome. Sequences surrounding implicated downstream AUG start codons are associated with nucleotide preferences with a pronounced three-base periodicity N1^G2^A3.
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Affiliation(s)
- Brynne E Lycette
- Department of Biology, Wesleyan University , Middletown, Connecticut 06459, United States.,Department of Mathematics and Computer Science, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Jacob W Glickman
- Department of Biology, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Samuel J Roth
- Department of Biology, Wesleyan University , Middletown, Connecticut 06459, United States.,Department of Mathematics and Computer Science, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Abigail E Cram
- Department of Biology, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Tae Hee Kim
- Department of Biology, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Danny Krizanc
- Department of Mathematics and Computer Science, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Michael P Weir
- Department of Biology, Wesleyan University , Middletown, Connecticut 06459, United States
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4
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Leon DR, Ytterberg AJ, Boontheung P, Kim U, Loo JA, Gunsalus RP, Ogorzalek Loo RR. Mining proteomic data to expose protein modifications in Methanosarcina mazei strain Gö1. Front Microbiol 2015; 6:149. [PMID: 25798134 PMCID: PMC4350412 DOI: 10.3389/fmicb.2015.00149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 02/09/2015] [Indexed: 12/11/2022] Open
Abstract
Proteomic tools identify constituents of complex mixtures, often delivering long lists of identified proteins. The high-throughput methods excel at matching tandem mass spectrometry data to spectra predicted from sequence databases. Unassigned mass spectra are ignored, but could, in principle, provide valuable information on unanticipated modifications and improve protein annotations while consuming limited quantities of material. Strategies to "mine" information from these discards are presented, along with discussion of features that, when present, provide strong support for modifications. In this study we mined LC-MS/MS datasets of proteolytically-digested concanavalin A pull down fractions from Methanosarcina mazei Gö1 cell lysates. Analyses identified 154 proteins. Many of the observed proteins displayed post-translationally modified forms, including O-formylated and methyl-esterified segments that appear biologically relevant (i.e., not artifacts of sample handling). Interesting cleavages and modifications (e.g., S-cyanylation and trimethylation) were observed near catalytic sites of methanogenesis enzymes. Of 31 Methanosarcina protein N-termini recovered by concanavalin A binding or from a previous study, only M. mazei S-layer protein MM1976 and its M. acetivorans C2A orthologue, MA0829, underwent signal peptide excision. Experimental results contrast with predictions from algorithms SignalP 3.0 and Exprot, which were found to over-predict the presence of signal peptides. Proteins MM0002, MM0716, MM1364, and MM1976 were found to be glycosylated, and employing chromatography tailored specifically for glycopeptides will likely reveal more. This study supplements limited, existing experimental datasets of mature archaeal N-termini, including presence or absence of signal peptides, translation initiation sites, and other processing. Methanosarcina surface and membrane proteins are richly modified.
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Affiliation(s)
- Deborah R Leon
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - A Jimmy Ytterberg
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - Pinmanee Boontheung
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - Unmi Kim
- Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles Los Angeles, CA, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA ; Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
| | - Robert P Gunsalus
- Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
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5
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Lin MS, Cherny JJ, Fournier CT, Roth SJ, Krizanc D, Weir MP. Assessment of MS/MS search algorithms with parent-protein profiling. J Proteome Res 2014; 13:1823-32. [PMID: 24533481 PMCID: PMC3993968 DOI: 10.1021/pr401090d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
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Peptide
mass spectrometry relies crucially on algorithms that match
peptides to spectra. We describe a method to evaluate the accuracy
of these algorithms based on the masses of parent proteins before
trypsin endoprotease digestion. Measurement of conformance to parent
proteins provides a score for comparison of the performances of different
algorithms as well as alternative parameter settings for a given algorithm.
Tracking of conformance scores for spectrum matches to proteins with
progressively lower expression levels revealed that conformance scores
are not uniform within data sets but are significantly lower for less
abundant proteins. Similarly peptides with lower algorithm peptide-spectrum
match scores have lower conformance. Although peptide mass spectrometry
data is typically filtered through decoy analysis to ensure a low
false discovery rate, this analysis confirms that the filtered data
should not be considered as having a uniform confidence. The analysis
suggests that use of different algorithms and multiple standardized
parameter settings of these algorithms can increase significantly
the numbers of peptides identified. This data set can be used as a
resource for future algorithm assessment.
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Affiliation(s)
- Miin S Lin
- Department of Biology and ‡Department of Mathematics and Computer Science, Wesleyan University Middletown Connecticut 06459, United States
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6
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Effect of different parameters on the hydrolytic activity of cross-linked enzyme aggregates (CLEAs) of lipase from Thermomyces lanuginosa. Biochem Eng J 2013. [DOI: 10.1016/j.bej.2012.12.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Fournier CT, Cherny JJ, Truncali K, Robbins-Pianka A, Lin MS, Krizanc D, Weir MP. Amino termini of many yeast proteins map to downstream start codons. J Proteome Res 2012; 11:5712-9. [PMID: 23140384 DOI: 10.1021/pr300538f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Comprehensive knowledge of proteome complexity is crucial to understanding cell function. Amino termini of yeast proteins were identified through peptide mass spectrometry on glutaraldehyde-treated cell lysates as well as a parallel assessment of publicly deposited spectra. An unexpectedly large fraction of detected amino-terminal peptides (35%) mapped to translation initiation at AUG codons downstream of the annotated start codon. Many of the implicated genes have suboptimal sequence contexts for translation initiation near their annotated AUG, and their ribosome profiles show elevated tag densities consistent with translation initiation at downstream AUGs as well as their annotated AUGs. These data suggest that a significant fraction of the yeast proteome derives from initiation at downstream AUGs, increasing significantly the repertoire of encoded proteins and their potential functions and cellular localizations.
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Affiliation(s)
- Claire T Fournier
- Department of Biology, Wesleyan University, Middletown, Connecticut 06459, United States
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8
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Krusemark CJ, Frey BL, Smith LM, Belshaw PJ. Complete chemical modification of amine and acid functional groups of peptides and small proteins. Methods Mol Biol 2011; 753:77-91. [PMID: 21604117 PMCID: PMC3859371 DOI: 10.1007/978-1-61779-148-2_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
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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9
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Zeng Q, Sun XN, Ma LH, Chen L, Wang Y, Chen C, Ye ZY, Wu ZH, Li YZ, Xu Y. Biomarkers for the Prediction of Major Adverse Cardiovascular Events in Patients With Acute Coronary Syndrome. Anat Rec (Hoboken) 2010; 293:1512-8. [DOI: 10.1002/ar.21198] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Moore BD, Rangachari V, Tay WM, Milkovic NM, Rosenberry TL. Biophysical analyses of synthetic amyloid-beta(1-42) aggregates before and after covalent cross-linking. Implications for deducing the structure of endogenous amyloid-beta oligomers. Biochemistry 2010; 48:11796-806. [PMID: 19916493 DOI: 10.1021/bi901571t] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A neuropathological hallmark of Alzheimer's disease (AD) is the presence of large numbers of senile plaques in the brain. These deposits are rich in fibrils that are composed of 40- and 42-residue amyloid-beta (Abeta) peptides. Several lines of evidence indicate that soluble Abeta aggregates as well as fibrils are important in the etiology of AD. Low levels of endogenous soluble Abeta aggregates make them difficult to characterize, but several species in extracts of AD brains have been detected by gel electrophoresis in sodium dodecyl sulfate (SDS) and immunoblotting. Individual Abeta oligomers ranging in size from dimers through dodecamers of 4 kDa monomeric Abeta have been resolved in other laboratories as discrete species by size exclusion chromatography (SEC). In an effort to reconstitute soluble Abeta aggregates in vitro that resemble the endogenous soluble Abeta aggregates, we previously found that monomeric Abeta(1-42) rapidly forms soluble oligomers in the presence of dilute SDS micelles. Here we extend this work in two directions. First, we contrast the size and secondary structure of these oligomers with those of synthetic Abeta(1-42) fibrils. SEC and multiangle light scattering were used to obtain a molecular mass of 150 kDa for the isolated oligomers. The oligomers partially dissociated to monomers through nonamers when incubated with SDS, but in contrast to endogenous oligomers, we saw no evidence of these discrete species prior to SDS treatment. One hypothesis to explain this difference is that endogenous oligomers are stabilized by covalent cross-linking induced by unknown cellular agents. To explore this hypothesis, optimal mass spectrometry (MS) analysis procedures need to be developed for Abeta cross-linked in vitro. In our second series of studies, we began this process by treating monomeric and aggregated Abeta(1-42) with three cross-linking agents: transglutaminase, glutaraldehyde, and Cu(II) with peroxide. We compared the efficiency of covalent cross-linking with these agents, the effect of cross-linking on peptide secondary structure, the stability of the cross-linked structures to thermal unfolding, and the sites of peptide cross-linking obtained from proteolysis and MS.
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Affiliation(s)
- Brenda D Moore
- Department of Neuroscience, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
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11
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Inhibitors selective for mycobacterial versus human proteasomes. Nature 2009; 461:621-6. [PMID: 19759536 PMCID: PMC3172082 DOI: 10.1038/nature08357] [Citation(s) in RCA: 175] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 08/04/2009] [Indexed: 12/20/2022]
Abstract
Many anti-infectives inhibit the synthesis of bacterial proteins, but none selectively inhibits their degradation. Most anti-infectives kill replicating pathogens, but few preferentially kill pathogens that have been forced into a non-replicating state by conditions in the host. To explore these alternative approaches we sought selective inhibitors of the proteasome of Mycobacterium tuberculosis (Mtb). Given that proteasome structure is extensively conserved, it is not surprising that inhibitors of all chemical classes tested have blocked both eukaryotic and prokaryotic proteasomes, and no inhibitor has proved substantially more potent on proteasomes of pathogens than of their hosts. Here we show that certain oxathiazol-2-ones kill non-replicating Mtb and act as selective suicide-substrate inhibitors of the Mtb proteasome by cyclo-carbonylating its active site threonine. Major conformational changes protect the inhibitor-enzyme intermediate from hydrolysis, allowing formation of an oxazolidin-2-one and preventing regeneration of active protease. Residues outside the active site whose H-bonds stabilize the critical loop before and after it moves are extensively non-conserved. This may account for the ability of oxathiazol-2-ones to inhibit the mycobacterial proteasome potently and irreversibly while largely sparing the human homolog.
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12
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Shi Y, Bajrami B, Yao X. Passive and Active Fragment Ion Mass Defect Labeling: Distinct Proteomics Potential of Iodine-Based Reagents. Anal Chem 2009; 81:6438-48. [DOI: 10.1021/ac9008034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Shi
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269
| | - Bekim Bajrami
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269
| | - Xudong Yao
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269
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13
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Abstract
Disulfide-rich peptide venoms from animals such as snakes, spiders, scorpions, and certain marine snails represent one of nature's great diversity libraries of bioactive molecules. The various species of marine cone shells have alone been estimated to produce >50,000 distinct peptide venoms. These peptides have stimulated considerable interest because of their ability to potently alter the function of specific ion channels. To date, only a small fraction of this immense resource has been characterized because of the difficulty in elucidating their primary structures, which range in size between 10 and 80 aa, include up to 5 disulfide bonds, and can contain extensive posttranslational modifications. The extraordinary complexity of crude venoms and the lack of DNA databases for many of the organisms of interest present major analytical challenges. Here, we describe a strategy that uses mass spectrometry for the elucidation of the mature peptide toxin components of crude venom samples. Key to this strategy is our use of electron transfer dissociation (ETD), a mass spectrometric fragmentation technique that can produce sequence information across the entire peptide backbone. However, because ETD only yields comprehensive sequence coverage when the charge state of the precursor peptide ion is sufficiently high and the m/z ratio is low, we combined ETD with a targeted chemical derivatization strategy to increase the charge state of cysteine-containing peptide toxins. Using this strategy, we obtained full sequences for 31 peptide toxins, using just 7% of the crude venom from the venom gland of a single cone snail (Conus textile).
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