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Wang T, Wang Z, Wang R, Zhang L, Zhang Y, Lu H. Highly efficient and chemoselective blocking of free amino group by ortho-phthalaldehyde (OPA) for comprehensive analysis of protein terminome. Talanta 2024; 267:125262. [PMID: 37804787 DOI: 10.1016/j.talanta.2023.125262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/24/2023] [Accepted: 09/30/2023] [Indexed: 10/09/2023]
Abstract
Herein, we introduced ortho-phthalaldehyde (OPA) for blocking free amino groups and established a simple and robust method for comprehensive profiling of protein terminome based on strong cation exchange chromatography (SCX) fractionation. With the highly efficient and chemoseletive amine-group blocking, we identified 2271 canonical human protein N-termini, 1650 canonical human protein C-termini, as well as 645 protein neo-N-termini from HeLa cells.
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Affiliation(s)
- Ting Wang
- Department of Chemistry and Liver Cancer Institute of Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Zhongjie Wang
- Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China
| | - Rui Wang
- Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China
| | - Lei Zhang
- Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China
| | - Ying Zhang
- Department of Chemistry and Liver Cancer Institute of Zhongshan Hospital, Fudan University, Shanghai, 200032, China; Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China.
| | - Haojie Lu
- Department of Chemistry and Liver Cancer Institute of Zhongshan Hospital, Fudan University, Shanghai, 200032, China; Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China.
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2
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Wang R, Wang Z, Lu H. Separation methods for system-wide profiling of protein terminome. Proteomics 2023; 23:e2100374. [PMID: 35997653 DOI: 10.1002/pmic.202100374] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/10/2022]
Abstract
Protein N- and C-termini have specific biochemical properties and functions. They play vital roles in various biological processes, such as protein stability and localization. In addition, post-translational modifications and proteolytic processing generate different proteoforms at protein termini. In recent years, terminomics has attracted significant attention, and numerous strategies have been developed to achieve high-throughput and global terminomics analysis. This review summarizes the recent protein N-termini and C-termini enrichment methods and their application in different samples. We also look ahead further application of terminomics in profiling protease substrates and discovery of disease biomarkers and therapeutic targets.
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Affiliation(s)
- Rui Wang
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Zhongjie Wang
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Haojie Lu
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China.,Department of Chemistry and Key Laboratory of Glycoconjugates Research Ministry of Public Health, Fudan University, Shanghai, People's Republic of China
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3
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Zhai L, Wang L, Hu H, Liu Q, Lee S, Tan M, Zhang Y. PBC, an easy and efficient strategy for high-throughput protein C-terminome profiling. Front Cell Dev Biol 2022; 10:995590. [PMID: 36120566 PMCID: PMC9471192 DOI: 10.3389/fcell.2022.995590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
High-throughput profiling of protein C-termini is still a challenging task. Proteomics provides a powerful technology for systematic and high-throughput study of protein C-termini. Various C-terminal peptide enrichment strategies based on chemical derivatization and chromatography separation have been reported. However, they are still costly and time-consuming, with low enrichment efficiency for C-terminal peptides. In this study, by taking advantage of the high reaction selectivity of 2-pyridinecarboxaldehyde (2-PCA) with an α-amino group on peptide N-terminus and high affinity between biotin and streptavidin, we developed a 2-PCA- and biotin labeling–based C-terminomic (PBC) strategy for a high-efficiency and high-throughput analysis of protein C-terminome. Triplicates of PBC experiments identified a total of 1,975 C-terminal peptides corresponding to 1,190 proteins from 293 T cell line, which is 180% higher than the highest reported number of C-terminal peptides identified from mammalian cells by chemical derivatization–based C-terminomics study. The enrichment efficiency (68%) is the highest among the C-terminomics methods currently reported. In addition, we not only uncovered 50 proteins with truncated C-termini which were significantly enriched in extracellular exosome, vesicle, and ribosome by a bioinformatic analysis but also systematically characterized the whole PTMs on C-terminal in 293 T cells, suggesting PBC as a powerful tool for protein C-terminal degradomics and PTMs investigation. In conclusion, the PBC strategy would benefit high-efficiency and high-throughput profiling of protein C-terminome.
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Affiliation(s)
- Linhui Zhai
- School of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
- Jiangsu Key Laboratory for Functional Substances of Chinese Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Le Wang
- School of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Hao Hu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Quan Liu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Sangkyu Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, South Korea
| | - Minjia Tan
- School of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Minjia Tan, ; Yinan Zhang,
| | - Yinan Zhang
- School of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
- Jiangsu Key Laboratory for Functional Substances of Chinese Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
- *Correspondence: Minjia Tan, ; Yinan Zhang,
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Lu J, Wang T, Bao H, Lu H. Fractionation-free negative enriching for in-depth C-terminome analysis. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2021.08.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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基于精氨酸酶切的蛋白质C端肽段富集方法的优化及评估. Se Pu 2022; 40:17-27. [PMID: 34985212 PMCID: PMC9404053 DOI: 10.3724/sp.j.1123.2021.03030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
基于聚合物的蛋白质C端反向富集策略是用于研究蛋白质C端最为广泛的策略之一。目前,基于胰蛋白酶(trypsin)切割精氨酸残基C端(ArgC型酶切)的蛋白C端组学方法对蛋白质C端的鉴定深度仍有待提高。为解决这一问题,该研究对此方法进行了优化和评估:建立了基于“V型”过滤装置的“一锅法”富集流程,避免了副反应的干扰,缩短了样本的制备时间;优化了蛋白水平乙酰化反应条件,最大限度地降低了丝氨酸、苏氨酸、酪氨酸残基上的副反应,提高了肽段鉴定的可信性;优化了基于固相萃取枪头膜片过滤柱(StageTip柱)的样品分离过程,使C端肽段的鉴定深度增加至原来的4倍。通过以上优化,按照肽段水平错误发现率(FDR)<0.01、离子分数(ion score)≥20,且C端带有乙醇胺修饰的数据筛选标准,从人HEK 293T细胞中共鉴定出696个蛋白质C端。若仅要求肽段水平FDR<0.01,鉴定数目进一步增加到933个,这是基于聚合物富集策略的蛋白质C端组学方法所得的最大数据集之一。探索了胰蛋白酶镜像酶(LysargiNase)切割精氨酸残基N端(ArgN型酶切)与不同肽段N端衍生化修饰组合对蛋白质C端鉴定数目和种类的影响,“LysargiNase酶切+肽段N端乙酰化”新策略在原有“胰蛋白酶酶切+肽段N端二甲基化”策略的基础上将鉴定蛋白质C端的种类提升了47%。综上,该研究通过对基于Arg型酶切的蛋白C端组学方法的优化,提升了C端肽段的鉴定深度,扩大了C端肽段鉴定的覆盖范围。该方法将有望成为系统性表征蛋白质C端的有力工具。
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Nishida H, Ishihama Y. One-Step Isolation of Protein C-Terminal Peptides from V8 Protease-Digested Proteins by Metal Oxide-Based Ligand-Exchange Chromatography. Anal Chem 2021; 94:944-951. [PMID: 34962382 DOI: 10.1021/acs.analchem.1c03722] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have developed a one-step method to isolate protein C-terminal peptides from V8 protease-digested proteins by metal oxide-based ligand-exchange (MOLEX) chromatography. V8 protease cleaves the C-terminal side of Asp and Glu, affording a digested peptide with two carboxy groups at the C-terminus, whereas the protein C-terminal peptide has only one α-carboxy group. In MOLEX chromatography, a stable chelate is formed between dicarboxylates and metal atoms, so that the nonterminal (i.e., internal) peptide is retained, whereas the protein C-terminal peptide flows through the MOLEX column. After the optimization of the MOLEX chromatographic conditions, 1619 protein C-termini were identified from 30 μg of peptides (10 μg each, in triplicate) derived from human HeLa cells by means of nanoLC/MS/MS. When the MOLEX-isolated sample from 200 μg of HeLa peptides was further divided into six fractions by high-pH reversed-phase liquid chromatography (LC) prior to nanoLC/MS/MS, 2203 protein C-termini were identified with less than 3% contamination with internal peptides. We believe that this is the largest coverage with the highest purity reported to date in human protein C-terminomics. This fast, simple, sensitive, and selective method to isolate protein C-terminal peptides should be useful for profiling protein C-termini on a proteome-wide scale.
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Affiliation(s)
- Hiroshi Nishida
- Department of Molecular & Cellular Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Yasushi Ishihama
- Department of Molecular & Cellular Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.,National Institute of Biomedical Innovation, Health and Nutrition, Laboratory of Clinical and Analytical Chemistry, Ibaraki, Osaka 567-0085, Japan
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7
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Wang Z, Zhang L, Yuan W, Zhang Y, Lu H. SAPT, a Fast and Efficient Approach for Simultaneous Profiling of Protein N- and C-Terminome. Anal Chem 2021; 93:10553-10560. [PMID: 34297549 DOI: 10.1021/acs.analchem.1c01598] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Protein termini play pivotal roles in various biological processes. Although several terminomic strategies have been proposed for the analysis of protein N-termini or protein C-termini separately, few can analyze both ends of proteins at the same time. Herein, we developed a workflow, termed Simultaneous Analysis of Protein N- and C-Terminome (SAPT) based on strong cation exchange chromatography (SCX) fractionation. Taking advantage of terminal peptides' reduced charge states in low pH SCX for their selective separation, we identified 3724 canonical human protein N-termini and 3129 canonical human protein C-termini, as well as 1463 neo-N-termini from the HeLa cell line, representing the largest human protein C-termini data set and the second largest human protein N-termini data set so far. The whole fractionation procedure was simple and rapid with considerable selectivity by utilizing a commercially available SCX-SPE column. In addition, we report for the first time the comprehensive screening of protein N-terminal and C-terminal modifications, leading to an identification of 8 kinds of protein N-terminal PTMs other than acetylation and 1 kind of protein C-terminal PTM other than amidation. Our results demonstrate the excellent performance and great potential of SAPT in terminomic studies. Data are available via ProteomeXchange with identifier PXD024573.
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Affiliation(s)
- Zhongjie Wang
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, P. R. China
| | - Lei Zhang
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, P. R. China
| | - Wenjuan Yuan
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, P. R. China
| | - Ying Zhang
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, P. R. China.,Department of Chemistry and Key Laboratory of Glycoconjugates Research Ministry of Public Health, Fudan University, Shanghai 200433, P. R. China
| | - Haojie Lu
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, P. R. China.,Department of Chemistry and Key Laboratory of Glycoconjugates Research Ministry of Public Health, Fudan University, Shanghai 200433, P. R. China
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8
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Li Q, Zhang Y, Wu Z, Huang J, Yue N, Huang L, Zhang X. Tyrosine-EDC Conjugation, an Undesirable Side Effect of the EDC-Catalyzed Carboxyl Labeling Approach. Anal Chem 2021; 93:697-703. [PMID: 33290043 DOI: 10.1021/acs.analchem.0c03487] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Carbodiimide-catalyzed carboxyl and amine conjugation (amidation) has been widely used to protect carboxyl groups. N-(3-(Dimethylamino)propyl)-N'-ethylcarbodiimide (EDC) is the most common carbodiimide reagent in protein chemistry due to its high catalytic efficiency in aqueous media. The reaction has also been applied in different proteomic studies including protein terminomics, glycosylation, and interaction. Herein, we report that the EDC-catalyzed amidation could cause a +155 Da side modification on the tyrosine residue and severely hamper the identification of Tyr-containing peptides. We revealed the extremely low identification rate of Tyr-containing peptides in different published studies employing the EDC-catalyzed amidation. We discovered a +155 Da side modification occurring specifically on Tyr and decoded it as the addition of EDC. Consideration of the side modification in a database search enabled the identification of 13 times more Tyr-containing peptides. Furthermore, we successfully developed an efficient method to remove the side modification. Our results also imply that chemical reactions in proteomic studies should be carefully evaluated prior to their wide applications. Data are available via ProteomeXchange with identifier PXD020042.
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Affiliation(s)
- Qingqing Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yang Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Zhen Wu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jingnan Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Ningning Yue
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Lin Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xumin Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
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9
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Yang C, Liu J, Hu Y, Dai Z, Liang Z, Shan Y, Zhang L, Zhang Y. Combination of continuous digestion by peptidase and spectral similarity comparisons for peptide sequencing. J Sep Sci 2021; 43:3665-3673. [PMID: 33405339 DOI: 10.1002/jssc.202000459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 11/10/2022]
Abstract
Peptide sequencing is critical to the quality control of peptide drugs and functional studies of active peptides. A combination of peptidase digestion and mass spectrometry technology is common for peptide sequencing. However, such methods often cannot obtain the complete sequence of a peptide due to insufficient amino acid sequence information. Here, we developed a method of generating full peptide ladders and comparing their MS2 spectral similarities. The peptide ladders, of which each component was different from the next component with one residue, were generated by continuous digestion by peptidase (carboxypeptidase Y and aminopeptidase). Then, based on the characteristics of peptide ladders, complete sequencing was realized by comparing MS2 spectral similarity of the generated peptide ladders. The complete amino acid sequences of bivalirudin, adrenocorticotropic hormone, and oxytocin were determined with high accuracy. This approach is beneficial to the quality control of drug peptides as well as the identification of novel bioactive peptides.
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Affiliation(s)
- Chao Yang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China.,University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Jianhui Liu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China
| | - Yechen Hu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China
| | - Zhongpeng Dai
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China
| | - Zhen Liang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China
| | - Yichu Shan
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China
| | - Lihua Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China
| | - Yukui Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China
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Chen L, Shan Y, Yang C, Sui Z, Zhang X, Zhang L, Zhang Y. Carboxypeptidase B-Assisted Charge-Based Fractional Diagonal Chromatography for Deep Screening of C-Terminome. Anal Chem 2020; 92:8005-8009. [DOI: 10.1021/acs.analchem.0c00762] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Lingfan Chen
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Fujian Province New Drug Safety Evaluation Centre, Fujian Medical University, Fuzhou 350108, China
| | - Yichu Shan
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Chao Yang
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zhigang Sui
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xiaodan Zhang
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Lihua Zhang
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yukui Zhang
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Wu Q, Tian Y, Yang C, Liang Z, Shan Y, Zhang L, Zhang Y. Sequential amidation of peptide C-termini for improving fragmentation efficiency. JOURNAL OF MASS SPECTROMETRY : JMS 2020; 56:e4529. [PMID: 32419269 DOI: 10.1002/jms.4529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/23/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
Owing to the poor fragmentation efficiency caused by the lack of a positively charged basic group at the C-termini of peptides, the identification of nontryptic peptides in classical proteomics is known to be less efficient. Particularly, attaching positively charged basic groups to C-termini via chemical derivatizations is known to be able to enhance their fragmentation efficiency. In this study, we introduced a novel strategy, C-termini sequential amidation reaction (CSAR), to improve peptide fragmentation efficiency. By this strategy, C-terminal and side-chain carboxyl groups were firstly amidated by neutral methylamine (MA), and then C-terminal amide bonds were selectively deamidated through peptide amidase while side-chain amide bonds remained unchanged, followed by the secondary amidation of C-termini via basic agmatine (AG). We optimized the amidation reaction conditions to achieve the MA derivatization efficiency of >99% for side-chain carboxyl groups and AG derivatization efficiency of 80% for the hydrolytic C-termini. We applied CSAR strategy to identify bovine serum albumin (BSA) chymotryptic digests, resulting in the increased fragmentation efficiencies (improvement by 9-32%) and charge states (improvement by 39-52%) under single or multiple dissociation modes. The strategy described here might be a promising approach for the identification of peptides that suffered from poor fragmentation efficiency.
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Affiliation(s)
- Qiong Wu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China
| | - Yu'e Tian
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chao Yang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China
| | - Zhen Liang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China
| | - Yichu Shan
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China
| | - Lihua Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China
| | - Yukui Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023, China
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12
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Li Q, Zhang Y, Huang J, Wu Z, Tang L, Huang L, Zhang X. Basic Strong Cation Exchange Chromatography, BaSCX, a Highly Efficient Approach for C-Terminomic Studies Using LysargiNase Digestion. Anal Chem 2020; 92:4742-4748. [DOI: 10.1021/acs.analchem.9b05280] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Qingqing Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yang Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jingnan Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Zhen Wu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Langlang Tang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Lin Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xumin Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
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13
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Niedermaier S, Huesgen PF. Positional proteomics for identification of secreted proteoforms released by site-specific processing of membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:140138. [DOI: 10.1016/j.bbapap.2018.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/31/2018] [Accepted: 09/13/2018] [Indexed: 02/06/2023]
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14
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Hu H, Zhao W, Zhu M, Zhao L, Zhai L, Xu JY, Liu P, Tan M. LysargiNase and Chemical Derivatization Based Strategy for Facilitating In-Depth Profiling of C-Terminome. Anal Chem 2019; 91:14522-14529. [PMID: 31634432 DOI: 10.1021/acs.analchem.9b03543] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Global identification of protein C-termini is highly challenging due to their low abundance in conventional shotgun proteomics. Several enrichment strategies have been developed to facilitate the detection of C-terminal peptides. One major issue of previous approaches is the limited C-terminome coverage. Herein, we integrated LysargiNase digestion, chemical acetylation on neo-N-terminus, and a-ion-aided peptide matching into poly(allylamine)-based C-terminomics (termed as LAACTer). In this strategy, we leveraged LysargiNase, a protease with cleavage specificity N-terminal to Lys and Arg residues, to cover previously unidentifiable C-terminome and employed chemical acetylation and a-ion-aided peptide matching to efficiently boost peptide identifications. Triplicates of LAACTer identified a total of 834 C-termini from proteome of 293T cell, which expanded the coverage by 164% (643 more unique C-termini) compared with the parallel experiments using the original workflow. Compared with the largest human C-terminome data sets (containing 800-900 C-termini), LAACTer not only achieved comparable profiling depth but also yielded 465 previously unidentified C-termini. In a SILAC (stable isotope labeling with amino acids in cell culture)-based quantitative study for identification of GluC-cleaved products, LAACTer quantified 300% more C-terminal peptides than the original workflow. Using LAACTer and the original workflow, we performed global analysis for the C-terminal sequences of 293T cell. The original and processed C-termini displayed distinct sequence patterns, implying the "C-end rules" that regulates protein stability could be more complex than just amino acid motifs. In conclusion, we reason LAACTer could be a powerful proteomic tool for in-depth C-terminomics and would benefit better functional understanding of protein C-termini.
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Affiliation(s)
- Hao Hu
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China
| | - Wensi Zhao
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China.,University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Mengdi Zhu
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China.,University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Lei Zhao
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China
| | - Linhui Zhai
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China
| | - Jun-Yu Xu
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China
| | - Ping Liu
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China
| | - Minjia Tan
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai , 201203 , China.,University of Chinese Academy of Sciences , Beijing 100049 , China
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15
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Du X, Fang C, Yang L, Bao H, Zhang L, Yan G, Lu H. In-Depth Analysis of C Terminomes Based on LysC Digestion and Site-Selective Dimethylation. Anal Chem 2019; 91:6498-6506. [DOI: 10.1021/acs.analchem.8b05338] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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16
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Perrar A, Dissmeyer N, Huesgen PF. New beginnings and new ends: methods for large-scale characterization of protein termini and their use in plant biology. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2021-2038. [PMID: 30838411 PMCID: PMC6460961 DOI: 10.1093/jxb/erz104] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/27/2019] [Indexed: 05/17/2023]
Abstract
Dynamic regulation of protein function and abundance plays an important role in virtually every aspect of plant life. Diversifying mechanisms at the RNA and protein level result in many protein molecules with distinct sequence and modification, termed proteoforms, arising from a single gene. Distinct protein termini define proteoforms arising from translation of alternative transcripts, use of alternative translation initiation sites, and different co- and post-translational modifications of the protein termini. Also site-specific proteolytic processing by endo- and exoproteases generates truncated proteoforms, defined by distinct protease-generated neo-N- and neo-C-termini, that may exhibit altered activity, function, and localization compared with their precursor proteins. In eukaryotes, the N-degron pathway targets cytosolic proteins, exposing destabilizing N-terminal amino acids and/or destabilizing N-terminal modifications for proteasomal degradation. This enables rapid and selective removal not only of unfolded proteins, but also of substrate proteoforms generated by proteolytic processing or changes in N-terminal modifications. Here we summarize current protocols enabling proteome-wide analysis of protein termini, which have provided important new insights into N-terminal modifications and protein stability determinants, protein maturation pathways, and protease-substrate relationships in plants.
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Affiliation(s)
- Andreas Perrar
- Forschungszentrum Jülich, Central Institute for Engineering, Electronics and Analytics, ZEA-3 Analytics, Jülich, Germany
| | - Nico Dissmeyer
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry (IPB), Weinberg, Halle (Saale), Germany
- ScienceCampus Halle – Plant-based Bioeconomy, Halle (Saale), Germany
| | - Pitter F Huesgen
- Forschungszentrum Jülich, Central Institute for Engineering, Electronics and Analytics, ZEA-3 Analytics, Jülich, Germany
- Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
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17
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Wu Z, Huang J, Huang J, Li Q, Zhang X. Lys-C/Arg-C, a More Specific and Efficient Digestion Approach for Proteomics Studies. Anal Chem 2018; 90:9700-9707. [DOI: 10.1021/acs.analchem.8b02448] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Zhen Wu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jichang Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jingnan Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Qingqing Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xumin Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
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18
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Solis N, Overall CM. Identification of Protease Cleavage Sites and Substrates in Cancer by Carboxy-TAILS (C-TAILS). Methods Mol Biol 2018; 1731:15-28. [PMID: 29318539 DOI: 10.1007/978-1-4939-7595-2_2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Determination of drug targets and development of novel therapeutics for the treatment of different cancers are actively ongoing areas of research. Proteases being the second largest group of enzymes in humans present themselves as attractive targets for blocking and activation to treat malignancies. However, determination of the protease cleavage substrates is often missed by utilizing conventional modern proteomic approaches. The relatively low abundance of proteolytically processed, and mostly semi-tryptic, peptides compared to tryptic peptides generated in shotgun proteomics compounded with their poorer identification rates makes the identification of such critical peptides challenging and so are mostly overlooked. Our laboratory introduced Terminal Amine Isotopic Labeling of Substrates (TAILS) to identify N-terminal peptides from cleavage events. In this chapter we present a protocol from our complementary method carboxy-TAILS (C-TAILS) to identify C-terminal peptides in metabolically labeled cancer cell lines.
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Affiliation(s)
- Nestor Solis
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC, Canada.,Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Christopher M Overall
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC, Canada. .,Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada. .,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
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19
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Klein T, Eckhard U, Dufour A, Solis N, Overall CM. Proteolytic Cleavage-Mechanisms, Function, and "Omic" Approaches for a Near-Ubiquitous Posttranslational Modification. Chem Rev 2017; 118:1137-1168. [PMID: 29265812 DOI: 10.1021/acs.chemrev.7b00120] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Proteases enzymatically hydrolyze peptide bonds in substrate proteins, resulting in a widespread, irreversible posttranslational modification of the protein's structure and biological function. Often regarded as a mere degradative mechanism in destruction of proteins or turnover in maintaining physiological homeostasis, recent research in the field of degradomics has led to the recognition of two main yet unexpected concepts. First, that targeted, limited proteolytic cleavage events by a wide repertoire of proteases are pivotal regulators of most, if not all, physiological and pathological processes. Second, an unexpected in vivo abundance of stable cleaved proteins revealed pervasive, functionally relevant protein processing in normal and diseased tissue-from 40 to 70% of proteins also occur in vivo as distinct stable proteoforms with undocumented N- or C-termini, meaning these proteoforms are stable functional cleavage products, most with unknown functional implications. In this Review, we discuss the structural biology aspects and mechanisms of catalysis by different protease classes. We also provide an overview of biological pathways that utilize specific proteolytic cleavage as a precision control mechanism in protein quality control, stability, localization, and maturation, as well as proteolytic cleavage as a mediator in signaling pathways. Lastly, we provide a comprehensive overview of analytical methods and approaches to study activity and substrates of proteolytic enzymes in relevant biological models, both historical and focusing on state of the art proteomics techniques in the field of degradomics research.
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Affiliation(s)
- Theo Klein
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Ulrich Eckhard
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Antoine Dufour
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Nestor Solis
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
| | - Christopher M Overall
- Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada
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20
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Zhang Y, Li Q, Huang J, Wu Z, Huang J, Huang L, Li Y, Ye J, Zhang X. An Approach to Incorporate Multi-Enzyme Digestion into C-TAILS for C-Terminomics Studies. Proteomics 2017; 18. [PMID: 29152854 DOI: 10.1002/pmic.201700034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 10/18/2017] [Indexed: 11/07/2022]
Abstract
Protein C-termini study is still a challenging task and far behind its counterpart, N-termini study. MS based C-terminomics study is often hampered by the low ionization efficiency of C-terminal peptides and the lack of efficient enrichment methods. We previously optimized the C-terminal amine-based isotope labeling of substrates (C-TAILS) method and identified 369 genuine protein C-termini in Escherichia coli. A key limitation of C-TAILS is that the prior protection of amines and carboxylic groups at protein level makes Arg-C as the only specific enzyme in practice. Herein, we report an approach combining multi-enzyme digestion and C-TAILS, which significantly increases the identification rate of C-terminal peptides and consequently improves the applicability of C-TAILS in biological studies. We carry out a systematic study and confirm that the omission of the prior amine protection at protein level has a negligible influence and allows the application of multi-enzyme digestion. We successfully apply five different enzyme digestions to C-TAILS, including trypsin, Arg-C, Lys-C, Lys-N, and Lysarginase. As a result, we identify a total of 722 protein C-termini in E. coli, which is at least 66% more than the results using any single enzyme. Moreover, the favored enzyme and enzyme combination are discovered. Data are available via ProteomeXchange with identifier PXD004275.
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Affiliation(s)
- Yang Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Qingqing Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Jingnan Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Zhen Wu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Jichang Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Lin Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Yanhong Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Juanying Ye
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Xumin Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
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21
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Huang J, Wang J, Li Q, Zhang Y, Zhang X. Enzyme and Chemical Assisted N-Terminal Blocked Peptides Analysis, ENCHANT, as a Selective Proteomics Approach Complementary to Conventional Shotgun Approach. J Proteome Res 2017; 17:212-221. [DOI: 10.1021/acs.jproteome.7b00521] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Jingnan Huang
- State Key Laboratory of Genetic
Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jie Wang
- State Key Laboratory of Genetic
Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Qingqing Li
- State Key Laboratory of Genetic
Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yang Zhang
- State Key Laboratory of Genetic
Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xumin Zhang
- State Key Laboratory of Genetic
Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
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22
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Chen L, Shan Y, Weng Y, Yuan H, Zhang S, Fan R, Sui Z, Zhang X, Zhang L, Zhang Y. Depletion of internal peptides by site-selective blocking, phosphate labeling, and TiO2 adsorption for in-depth analysis of C-terminome. Anal Bioanal Chem 2016; 408:3867-74. [DOI: 10.1007/s00216-016-9476-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 01/18/2023]
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23
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Somasundaram P, Koudelka T, Linke D, Tholey A. C-Terminal Charge-Reversal Derivatization and Parallel Use of Multiple Proteases Facilitates Identification of Protein C-Termini by C-Terminomics. J Proteome Res 2016; 15:1369-78. [PMID: 26939532 DOI: 10.1021/acs.jproteome.6b00146] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The identification of protein C-termini in complex proteomes is challenging due to the poor ionization efficiency of the carboxyl group. Amidating the negatively charged C-termini with ethanolamine (EA) has been suggested to improve the detection of C-terminal peptides and allows for a directed depletion of internal peptides after proteolysis using carboxyl reactive polymers. In the present study, the derivatization with N,N-dimethylethylenediamine (DMEDA) and (4-aminobutyl)guanidine (AG) leading to a positively charged C-terminus was investigated. C-terminal charge-reversed peptides showed improved coverage of b- and y-ion series in the MS/MS spectra compared to their noncharged counterparts. DMEDA-derivatized peptides resulted in many peptides with charge states of 3+, which benefited from ETD fragmentation. This makes the charge-reversal strategy particularly useful for the analysis of protein C-termini, which may also be post-translationally modified. The labeling strategy and the indirect enrichment of C-termini worked with similar efficiency for both DMEDA and EA, and their applicability was demonstrated on an E. coli proteome. Utilizing two proteases and different MS/MS activation mechanisms allowed for the identification of >400 C-termini, encompassing both canonical and truncated C-termini.
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Affiliation(s)
- Prasath Somasundaram
- AG Systematische Proteomforschung & Bioanalytik, Institut für Experimentelle Medizin, Christian-Albrechts-Universität zu Kiel , Niemannsweg 11, 24105 Kiel, Germany
| | - Tomas Koudelka
- AG Systematische Proteomforschung & Bioanalytik, Institut für Experimentelle Medizin, Christian-Albrechts-Universität zu Kiel , Niemannsweg 11, 24105 Kiel, Germany
| | - Dennis Linke
- AG Systematische Proteomforschung & Bioanalytik, Institut für Experimentelle Medizin, Christian-Albrechts-Universität zu Kiel , Niemannsweg 11, 24105 Kiel, Germany
| | - Andreas Tholey
- AG Systematische Proteomforschung & Bioanalytik, Institut für Experimentelle Medizin, Christian-Albrechts-Universität zu Kiel , Niemannsweg 11, 24105 Kiel, Germany
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