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Kerdraon F, Bogard G, Snella B, Drobecq H, Pichavant M, Agouridas V, Melnyk O. Insights into the Mechanism and Catalysis of Peptide Thioester Synthesis by Alkylselenols Provide a New Tool for Chemical Protein Synthesis. Molecules 2021; 26:1386. [PMID: 33806630 PMCID: PMC7961367 DOI: 10.3390/molecules26051386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 02/26/2021] [Accepted: 02/27/2021] [Indexed: 11/17/2022] Open
Abstract
While thiol-based catalysts are widely employed for chemical protein synthesis relying on peptide thioester chemistry, this is less true for selenol-based catalysts whose development is in its infancy. In this study, we compared different selenols derived from the selenocysteamine scaffold for their capacity to promote thiol-thioester exchanges in water at mildly acidic pH and the production of peptide thioesters from bis(2-sulfanylethyl)amido (SEA) peptides. The usefulness of a selected selenol compound is illustrated by the total synthesis of a biologically active human chemotactic protein, which plays an important role in innate and adaptive immunity.
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Affiliation(s)
- Florent Kerdraon
- U1019-UMR 9017—CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, University of Lille, CNRS, Inserm, CHU Lille, F-59000 Lille, France; (F.K.); (G.B.); (B.S.); (H.D.); (M.P.)
| | - Gemma Bogard
- U1019-UMR 9017—CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, University of Lille, CNRS, Inserm, CHU Lille, F-59000 Lille, France; (F.K.); (G.B.); (B.S.); (H.D.); (M.P.)
| | - Benoît Snella
- U1019-UMR 9017—CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, University of Lille, CNRS, Inserm, CHU Lille, F-59000 Lille, France; (F.K.); (G.B.); (B.S.); (H.D.); (M.P.)
| | - Hervé Drobecq
- U1019-UMR 9017—CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, University of Lille, CNRS, Inserm, CHU Lille, F-59000 Lille, France; (F.K.); (G.B.); (B.S.); (H.D.); (M.P.)
| | - Muriel Pichavant
- U1019-UMR 9017—CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, University of Lille, CNRS, Inserm, CHU Lille, F-59000 Lille, France; (F.K.); (G.B.); (B.S.); (H.D.); (M.P.)
| | - Vangelis Agouridas
- U1019-UMR 9017—CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, University of Lille, CNRS, Inserm, CHU Lille, F-59000 Lille, France; (F.K.); (G.B.); (B.S.); (H.D.); (M.P.)
- Centrale Lille, F-59000 Lille, France
| | - Oleg Melnyk
- U1019-UMR 9017—CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, University of Lille, CNRS, Inserm, CHU Lille, F-59000 Lille, France; (F.K.); (G.B.); (B.S.); (H.D.); (M.P.)
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2
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Arbour CA, Mendoza LG, Stockdill JL. Recent advances in the synthesis of C-terminally modified peptides. Org Biomol Chem 2020; 18:7253-7272. [PMID: 32914156 PMCID: PMC9508648 DOI: 10.1039/d0ob01417f] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
C-Terminally modified peptides are important for the development and delivery of peptide-based pharmaceuticals because they impact peptide activity, stability, hydrophobicity, and membrane permeability. Additionally, the vulnerability of C-terminal esters to cleavage by endogenous esterases makes them excellent pro-drugs. Methods for post-SPPS C-terminal functionalization potentially enable access to libraries of modified peptides, facilitating tailoring of their solubility, potency, toxicity, and uptake pathway. Apparently minor structural changes can significantly impact the binding, folding, and pharmacokinetics of the peptide. This review summarizes developments in chemical methods for C-terminal modification of peptides published since the last review on this topic in 2003.
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Affiliation(s)
- Christine A Arbour
- Wayne State University, Department of Chemistry, Detroit, Michigan, USA.
| | - Lawrence G Mendoza
- Wayne State University, Department of Chemistry, Detroit, Michigan, USA.
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3
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Acosta GA, Murray L, Royo M, de la Torre BG, Albericio F. Solid-Phase Synthesis of Head to Side-Chain Tyr-Cyclodepsipeptides Through a Cyclative Cleavage From Fmoc-MeDbz/MeNbz-resins. Front Chem 2020; 8:298. [PMID: 32391324 PMCID: PMC7189019 DOI: 10.3389/fchem.2020.00298] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/25/2020] [Indexed: 12/16/2022] Open
Abstract
Cyclic depsipeptides constitute a fascinating class of natural products. Most of them are characterized by an ester formed between the β-hydroxy function of Ser/Thr -and related amino acids- and the carboxylic group of the C-terminal amino acid. Less frequent are those where the thiol of Cys is involved rendering a thioester (cyclo thiodepsipeptides) and even less common are the cyclo depsipeptides with a phenyl ester coming from the side-chain of Tyr. Herein, the preparation of the later through a cyclative cleavage using the Fmoc-MeDbz/MeNbz-resin is described. This resin has previously reported for the synthesis of cyclo thiodepsipeptides and homodetic peptides. The use of that resin for the preparation of all these peptides is also summarized.
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Affiliation(s)
- Gerardo A Acosta
- CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, University of Barcelona (UB), Barcelona, Spain.,Department of Organic Chemistry, University of Barcelona, Barcelona, Spain.,Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), Spanish National Research Council (CSIC), Barcelona, Spain.,Associated Unit, Spanish National Research Council-University of Barcelona (CSIC-UB), Barcelona, Spain
| | - Laura Murray
- CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, University of Barcelona (UB), Barcelona, Spain.,Department of Organic Chemistry, University of Barcelona, Barcelona, Spain
| | - Miriam Royo
- Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), Spanish National Research Council (CSIC), Barcelona, Spain.,Associated Unit, Spanish National Research Council-University of Barcelona (CSIC-UB), Barcelona, Spain
| | - Beatriz G de la Torre
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.,Peptide Science Laboratory, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Fernando Albericio
- CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, University of Barcelona (UB), Barcelona, Spain.,Department of Organic Chemistry, University of Barcelona, Barcelona, Spain.,Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), Spanish National Research Council (CSIC), Barcelona, Spain.,Associated Unit, Spanish National Research Council-University of Barcelona (CSIC-UB), Barcelona, Spain.,Peptide Science Laboratory, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
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4
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Yanase M, Nakatsu K, Cardos CJ, Konda Y, Hayashi G, Okamoto A. Cysteinylprolyl imide (CPI) peptide: a highly reactive and easily accessible crypto-thioester for chemical protein synthesis. Chem Sci 2019; 10:5967-5975. [PMID: 31360403 PMCID: PMC6566460 DOI: 10.1039/c9sc00646j] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/09/2019] [Indexed: 12/21/2022] Open
Abstract
A new crypto-thioester, cysteinylprolyl imide (CPI) peptide, offers a practical synthetic pathway and reliable reaction rate to be successfully applied to chemical protein synthesis.
Native chemical ligation (NCL) between the C-terminal peptide thioester and the N-terminal cysteinyl-peptide revolutionized the field of chemical protein synthesis. The difficulty of direct synthesis of the peptide thioester in the Fmoc method has prompted the development of crypto-thioesters that can be efficiently converted into thioesters. Cysteinylprolyl ester (CPE), which is an N–S acyl shift-driven crypto-thioester that relies on an intramolecular O–N acyl shift to displace the amide-thioester equilibrium, enabled trans-thioesterification and subsequent NCL in one pot. However, the utility of CPE is limited because of the moderate thioesterification rates and the synthetic complexity introduced by the ester group. Herein, we develop a new crypto-thioester, cysteinylprolyl imide (CPI), which replaces the alcohol leaving group of CPE with other leaving groups such as benzimidazolidinone, oxazolidinone, and pyrrolidinone. CPI peptides were efficiently synthesized by using standard Fmoc solid-phase peptide synthesis (SPPS) and subsequent on-resin imide formation. Screening of the several imide structures indicated that methyloxazolidinone-t-leucine (MeOxd-Tle) showed faster conversion into thioester and higher stability against hydrolysis under NCL conditions. Finally, by using CPMeOxd-Tle peptides, we demonstrated the chemical synthesis of affibody via N-to-C sequential, three-segment ligation and histone H2A.Z via convergent four-segment ligation. This facile and straightforward method is expected to be broadly applicable to chemical protein synthesis.
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Affiliation(s)
- Masafumi Yanase
- Department of Chemistry and Biotechnology , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan .
| | - Koki Nakatsu
- Department of Chemistry and Biotechnology , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan .
| | - Charlane Joy Cardos
- Department of Chemistry and Biotechnology , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan .
| | - Yoshiki Konda
- Department of Chemistry and Biotechnology , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan .
| | - Gosuke Hayashi
- Department of Chemistry and Biotechnology , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan . .,Department of Biomolecular Engineering , Graduate School of Engineering , Nagoya University , Furo-cho, Chikusa-ku , Nagoya 464-8603 , Japan .
| | - Akimitsu Okamoto
- Department of Chemistry and Biotechnology , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan . .,Research Center for Advanced Science and Technology , The University of Tokyo , 4-6-1 Komaba, Meguro-ku , Tokyo 153-8904 , Japan
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5
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Agouridas V, El Mahdi O, Diemer V, Cargoët M, Monbaliu JCM, Melnyk O. Native Chemical Ligation and Extended Methods: Mechanisms, Catalysis, Scope, and Limitations. Chem Rev 2019; 119:7328-7443. [DOI: 10.1021/acs.chemrev.8b00712] [Citation(s) in RCA: 243] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Vangelis Agouridas
- UMR CNRS 8204, Centre d’Immunité et d’Infection de Lille, University of Lille, CNRS, Institut Pasteur de Lille, F-59000 Lille, France
| | - Ouafâa El Mahdi
- Faculté Polydisciplinaire de Taza, University Sidi Mohamed Ben Abdellah, BP 1223 Taza Gare, Morocco
| | - Vincent Diemer
- UMR CNRS 8204, Centre d’Immunité et d’Infection de Lille, University of Lille, CNRS, Institut Pasteur de Lille, F-59000 Lille, France
| | - Marine Cargoët
- UMR CNRS 8204, Centre d’Immunité et d’Infection de Lille, University of Lille, CNRS, Institut Pasteur de Lille, F-59000 Lille, France
| | - Jean-Christophe M. Monbaliu
- Center for Integrated Technology and Organic Synthesis, Department of Chemistry, University of Liège, Building B6a, Room 3/16a, Sart-Tilman, B-4000 Liège, Belgium
| | - Oleg Melnyk
- UMR CNRS 8204, Centre d’Immunité et d’Infection de Lille, University of Lille, CNRS, Institut Pasteur de Lille, F-59000 Lille, France
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6
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Yang YH, Di B, Yang DS. The discovery of a freezing-induced peptide ligation during the total chemical synthesis of human interferon-ε. Org Biomol Chem 2019; 16:5097-5101. [PMID: 29972388 DOI: 10.1039/c8ob01365a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A counterintuitive freezing-induced peptide ligation was discovered during the total synthesis of human interferon-ε (hIFN-ε) which blocks HIV infection through unique mechanisms. The successful synthesis of hIFN-ε (187 amino acids) in this research laid the foundation for related anti-AIDS drug development. Moreover, alanine mutation based on sequence alignment to solve the maldistribution of the ligation site and freezing-induced dominant conformation that facilitates peptide ligation are expected to be helpful for the synthesis of macrobiomolecules.
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Affiliation(s)
- Yin-He Yang
- Jiang Su Key Laboratory of Drug Design and Optimization, Key Laboratory on Protein Chemistry and Structural Biology, China Pharmaceutical University, Nanjing 210009, China.
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7
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Kent SBH. Novel protein science enabled by total chemical synthesis. Protein Sci 2018; 28:313-328. [PMID: 30345579 DOI: 10.1002/pro.3533] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 10/12/2018] [Accepted: 10/15/2018] [Indexed: 01/01/2023]
Abstract
Chemical synthesis is a well-established method for the preparation in the research laboratory of multiple-tens-of-milligram amounts of correctly folded, high purity protein molecules. Chemically synthesized proteins enable a broad spectrum of novel protein science. Racemic mixtures consisting of d-protein and l-protein enantiomers facilitate crystallization and determination of protein structures by X-ray diffraction. d-Proteins enable the systematic development of unnatural mirror image protein molecules that bind with high affinity to natural protein targets. The d-protein form of a therapeutic target can also be used to screen natural product libraries to identify novel small molecule leads for drug development. Proteins with novel polypeptide chain topologies including branched, circular, linear-loop, and interpenetrating polypeptide chains can be constructed by chemical synthesis. Medicinal chemistry can be applied to optimize the properties of therapeutic protein molecules. Chemical synthesis has been used to redesign glycoproteins and for the a priori design and construction of covalently constrained novel protein scaffolds not found in nature. Versatile and precise labeling of protein molecules by chemical synthesis facilitates effective application of advanced physical methods including multidimensional nuclear magnetic resonance and time-resolved FTIR for the elucidation of protein structure-activity relationships. The chemistries used for total synthesis of proteins have been adapted to making artificial molecular devices and protein-inspired nanomolecular constructs. Research to develop mirror image life in the laboratory is in its very earliest stages, based on the total chemical synthesis of d-protein forms of polymerase enzymes.
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Affiliation(s)
- Stephen B H Kent
- Department of Chemistry and Department of Biochemistry and Molecular Biology; Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, 60637
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8
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Bi S, Liu P, Ling B, Yuan X, Jiang Y. Mechanism of N-to-S acyl transfer of N-(2-hydroxybenzyl) cysteine derivatives and origin of phenol acceleration effect. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2017.11.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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9
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Yan B, Shi W, Ye L, Liu L. Acyl donors for native chemical ligation. Curr Opin Chem Biol 2018; 46:33-40. [PMID: 29654943 DOI: 10.1016/j.cbpa.2018.03.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 03/21/2018] [Accepted: 03/29/2018] [Indexed: 11/28/2022]
Abstract
Native chemical ligation (NCL) has become one of the most important methods in chemical syntheses of proteins. Recently, in order to expand its scope, considerable effort has been devoted to tuning the C-terminal acyl donor thioesters used in NCL. This article reviews the recent advances in the design of C-terminal acyl donors, their precursors and surrogates, and highlights some noteworthy progress that may lead the future direction of protein chemical synthesis.
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Affiliation(s)
- Bingjia Yan
- Tsinghua-Peking Center for Life Sciences, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Beijing Advanced Innovation Center for Structural Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Weiwei Shi
- Tsinghua-Peking Center for Life Sciences, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Beijing Advanced Innovation Center for Structural Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Linzhi Ye
- Tsinghua-Peking Center for Life Sciences, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Beijing Advanced Innovation Center for Structural Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- Tsinghua-Peking Center for Life Sciences, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Beijing Advanced Innovation Center for Structural Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
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10
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Wang Y, Han L, Yuan N, Wang H, Li H, Liu J, Chen H, Zhang Q, Dong S. Traceless β-mercaptan-assisted activation of valinyl benzimidazolinones in peptide ligations. Chem Sci 2018; 9:1940-1946. [PMID: 29675240 PMCID: PMC5892131 DOI: 10.1039/c7sc04148a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/04/2018] [Indexed: 12/27/2022] Open
Abstract
Peptidyl thioesters or their surrogates with C-terminal β-branched hydrophobic amino acid residues usually exhibit poor reactivities in ligation reactions. Thus, activation using exogenous additives is required to ensure an acceptable reaction efficiency. Herein, we report a traceless ligation at Val-Xaa sites under mild thiol additive-free reaction conditions, whereby the introduction of β-mercaptan on the C-terminal valine residue effectively activates the otherwise unreactive N-acyl-benzimidazolinone (Nbz), and enables the use of a one-pot ligation-desulfurization strategy to generate the desired peptide products. The orthogonality between β-thiovaline-Nbz and a conventional alkyl thioester, as well as the convenient access to the former from readily available penicillamine, also allowed expedited assembly of the peptidic hormone β-LPH and hPTH analogues, based on a kinetically controlled one-pot three-segment ligation and desulfurization strategy.
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Affiliation(s)
- Yinglu Wang
- State Key Laboratory of Natural and Biomimetic Drugs , Department of Chemical Biology , School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China .
| | - Lin Han
- State Key Laboratory of Natural and Biomimetic Drugs , Department of Chemical Biology , School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China .
| | - Ning Yuan
- State Key Laboratory of Natural and Biomimetic Drugs , Department of Chemical Biology , School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China .
| | - Hanxuan Wang
- State Key Laboratory of Natural and Biomimetic Drugs , Department of Chemical Biology , School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China .
| | - Hongxing Li
- State Key Laboratory of Natural and Biomimetic Drugs , Department of Chemical Biology , School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China .
| | - Jinrong Liu
- State Key Laboratory of Natural and Biomimetic Drugs , Department of Chemical Biology , School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China .
| | - Huan Chen
- Department of Chemistry , University at Albany , Albany , New York 12222 , USA .
| | - Qiang Zhang
- Department of Chemistry , University at Albany , Albany , New York 12222 , USA .
| | - Suwei Dong
- State Key Laboratory of Natural and Biomimetic Drugs , Department of Chemical Biology , School of Pharmaceutical Sciences , Peking University , Beijing 100191 , China .
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11
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Chen H, Xiao Y, Yuan N, Weng J, Gao P, Breindel L, Shekhtman A, Zhang Q. Coupling of sterically demanding peptides by β-thiolactone-mediated native chemical ligation. Chem Sci 2018; 9:1982-1988. [PMID: 29675245 PMCID: PMC5892351 DOI: 10.1039/c7sc04744d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/02/2018] [Indexed: 12/30/2022] Open
Abstract
The ligation of sterically demanding peptidyl sites such as those involving Val-Val and Val-Pro linkages has proven to be extremely challenging with conventional NCL methods that rely on exogenous thiol additives. Herein, we report an efficient β-thiolactone-mediated additive-free NCL protocol that enables the establishment of these connections in good yield. The rapid NCL was followed by in situ desulfurization. Reaction rates between β-thiolactones and conventional thioesters towards NCL were also investigated, and direct aminolysis was ruled out as a possible pathway. Finally, the potent cytotoxic cyclic-peptide axinastatin 1 has been prepared using the developed methodology.
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Affiliation(s)
- Huan Chen
- Department of Chemistry , University at Albany , State University of New York , 1400 Washington Avenue , Albany , NY 12222 , USA .
| | - Yunxian Xiao
- Department of Chemistry , University at Albany , State University of New York , 1400 Washington Avenue , Albany , NY 12222 , USA .
| | - Ning Yuan
- State Key Laboratory of Natural and Biomimetic Drugs , School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Beijing 100191 , China
| | - Jiaping Weng
- Department of Chemistry , University at Albany , State University of New York , 1400 Washington Avenue , Albany , NY 12222 , USA .
| | - Pengcheng Gao
- Department of Chemistry , University at Albany , State University of New York , 1400 Washington Avenue , Albany , NY 12222 , USA .
| | - Leonard Breindel
- Department of Chemistry , University at Albany , State University of New York , 1400 Washington Avenue , Albany , NY 12222 , USA
| | - Alexander Shekhtman
- Department of Chemistry , University at Albany , State University of New York , 1400 Washington Avenue , Albany , NY 12222 , USA
| | - Qiang Zhang
- Department of Chemistry , University at Albany , State University of New York , 1400 Washington Avenue , Albany , NY 12222 , USA .
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12
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Devaraj NK, Perrin CL. Approach control. Stereoelectronic origin of geometric constraints on N-to-S and N-to-O acyl shifts in peptides. Chem Sci 2018; 9:1789-1794. [PMID: 29675223 PMCID: PMC5892126 DOI: 10.1039/c7sc04046f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/06/2018] [Indexed: 11/21/2022] Open
Abstract
Intramolecular N-to-S or N-to-O acyl shifts in peptides are of fundamental and practical importance, as they constitute the first step in protein splicing and can be used for the synthesis of thioester-modified peptides required for native chemical ligation. It has been stated that the nucleophile must be positioned anti to the carbonyl oxygen, as in a cis amide. Despite the importance of such reactions, an understanding of this geometric restriction remains obscure. Here we argue that the empirical requirement for positioning the nucleophile is a stereoelectronic effect arising from the ease of approach of the nucleophile to a carbonyl group, not ground-state destabilization. DFT calculations on model amides support our explanation and indicate a significant decrease in both the transition-state energy and the activation energy for a cis amide. However, the approach of the nucleophile must be anti not only to the carbonyl oxygen but also to the nitrogen. The direction of approach is expressed by a new, modified Bürgi-Dunitz angle. Our data shed light on the mechanisms of acyl shifts in peptides, and they explain why a cis peptide might be required for protein splicing. The further implications for acyl shits in homoserine and homocysteine peptides and for aldol condensations are also considered.
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Affiliation(s)
- Neal K Devaraj
- Dept. of Chemistry & Biochemistry , Univ. Calif. San Diego , La Jolla , CA 92093-0358 , USA .
| | - Charles L Perrin
- Dept. of Chemistry & Biochemistry , Univ. Calif. San Diego , La Jolla , CA 92093-0358 , USA .
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