Pub Date : 2022-05-01Epub Date: 2022-01-06DOI: 10.1002/pep2.24254
Samir Bouayad-Gervais, Daniel J St-Cyr, Mathieu Courcelles, Éric Bonneil, Florence H Gohard, Pierre Thibault, William C Earnshaw, Mike Tyers
Genetically-encoded cyclic peptide libraries allow rapid in vivo screens for inhibitors of any target protein of interest. In particular, the Split Intein Circular Ligation of Protein and Peptides (SICLOPPS) system exploits spontaneous protein splicing of inteins to produce intracellular cyclic peptides. A previous SICLOPPS screen against Aurora B kinase, which plays a critical role during chromosome segregation, identified several candidate inhibitors that we sought to recapitulate by chemical synthesis. We describe the syntheses of cyclic peptide hits and analogs via solution-phase macrocyclization of side chain-protected linear peptides obtained from standard solid-phase peptide synthesis. Cyclic peptide targets, including cyclo-[CTWAR], were designed to match both the variable portions and conserved cysteine residue of their genetically-encoded counterparts. Synthetic products were characterized by tandem high-resolution mass spectrometry to analyze a combination of exact mass, isotopic pattern, and collisional dissociation-induced fragmentation pattern. The latter analyses facilitated the distinction between targets and oligomeric side products, and served to confirm peptidic sequences in a manner that can be readily extended to analyses of complex biological samples. This alternative chemical synthesis approach for cyclic peptides allows cost-effective validation and facile chemical elaboration of hit candidates from SICLOPPS screens.
通过基因编码的环肽库，可以在体内快速筛选出任何感兴趣的目标蛋白的抑制剂。特别是蛋白质和肽的分裂茵环连接（SICLOPPS）系统，它利用茵的自发蛋白质分裂产生细胞内环肽。SICLOPPS 之前针对在染色体分离过程中起关键作用的极光 B 激酶进行了筛选，发现了几种候选抑制剂，我们试图通过化学合成来重现这些抑制剂。我们介绍了通过标准固相肽合成获得的侧链保护线性肽的溶液相大环化合成环肽靶点和类似物的过程。环肽目标物（包括环[CTWAR]）的设计与基因编码对应物的可变部分和保守半胱氨酸残基相匹配。合成产物采用串联高分辨质谱法进行表征，结合精确质量、同位素模式和碰撞解离诱导碎片模式进行分析。后者的分析有助于区分目标物和低聚物副产品，并能以一种易于扩展到复杂生物样本分析的方式确认肽序列。这种环肽化学合成替代方法可以对 SICLOPPS 筛选出的候选靶标进行经济有效的验证和简便的化学阐述。
{"title":"Head-to-tail cyclization of side chain-protected linear peptides to recapitulate genetically-encoded cyclized peptides.","authors":"Samir Bouayad-Gervais, Daniel J St-Cyr, Mathieu Courcelles, Éric Bonneil, Florence H Gohard, Pierre Thibault, William C Earnshaw, Mike Tyers","doi":"10.1002/pep2.24254","DOIUrl":"10.1002/pep2.24254","url":null,"abstract":"<p><p>Genetically-encoded cyclic peptide libraries allow rapid <i>in vivo</i> screens for inhibitors of any target protein of interest. In particular, the Split Intein Circular Ligation of Protein and Peptides (SICLOPPS) system exploits spontaneous protein splicing of inteins to produce intracellular cyclic peptides. A previous SICLOPPS screen against Aurora B kinase, which plays a critical role during chromosome segregation, identified several candidate inhibitors that we sought to recapitulate by chemical synthesis. We describe the syntheses of cyclic peptide hits and analogs via solution-phase macrocyclization of side chain-protected linear peptides obtained from standard solid-phase peptide synthesis. Cyclic peptide targets, including cyclo-[CTWAR], were designed to match both the variable portions and conserved cysteine residue of their genetically-encoded counterparts. Synthetic products were characterized by tandem high-resolution mass spectrometry to analyze a combination of exact mass, isotopic pattern, and collisional dissociation-induced fragmentation pattern. The latter analyses facilitated the distinction between targets and oligomeric side products, and served to confirm peptidic sequences in a manner that can be readily extended to analyses of complex biological samples. This alternative chemical synthesis approach for cyclic peptides allows cost-effective validation and facile chemical elaboration of hit candidates from SICLOPPS screens.</p>","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":"114 3","pages":"e24254"},"PeriodicalIF":1.5,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9286623/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40543630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ability to reversibly modulate peptide secondary structures, such as the β‐turn, allows for precise control of biological function, including protein interactions. Herein, we describe the design of two scaffolds containing an azobenzene moiety with flanking alanine or β‐alanine residues to probe essential features for photo‐control of a β‐turn within a cyclic peptide. To efficiently cyclize the designed linear peptides, prior isomerization of the azobenzene‐containing amino acid from the trans to the cis form was necessary. The two cyclic peptides (TAp and TApβ) were found to undergo rapid photochemical conversion to the cis isomer of the azobenzene, with a more gradual thermal reversion to the trans isomer over the course of a week at 37 °C. Spectroscopic analysis and restrained molecular dynamics simulation of the cis form of TAp and TApβ revealed type II and type II' β‐turns within the cyclic peptides, respectively. The trans isomer of the TAp cyclic peptide was found to have a kink within the peptide structure, whereas the longer trans‐TApβ contained a more extended conformation. TApβ, therefore, demonstrates a clearer difference in the cyclic peptide conformations when in the cis versus trans form, a feature that may prove beneficial for use with biologically active β‐turn sequences.
{"title":"A refined photo‐switchable cyclic peptide scaffold for use in β‐turn activation","authors":"C. Johnson, J. Harwood, M. Lipton, J. Chmielewski","doi":"10.1002/pep2.24265","DOIUrl":"https://doi.org/10.1002/pep2.24265","url":null,"abstract":"The ability to reversibly modulate peptide secondary structures, such as the β‐turn, allows for precise control of biological function, including protein interactions. Herein, we describe the design of two scaffolds containing an azobenzene moiety with flanking alanine or β‐alanine residues to probe essential features for photo‐control of a β‐turn within a cyclic peptide. To efficiently cyclize the designed linear peptides, prior isomerization of the azobenzene‐containing amino acid from the trans to the cis form was necessary. The two cyclic peptides (TAp and TApβ) were found to undergo rapid photochemical conversion to the cis isomer of the azobenzene, with a more gradual thermal reversion to the trans isomer over the course of a week at 37 °C. Spectroscopic analysis and restrained molecular dynamics simulation of the cis form of TAp and TApβ revealed type II and type II' β‐turns within the cyclic peptides, respectively. The trans isomer of the TAp cyclic peptide was found to have a kink within the peptide structure, whereas the longer trans‐TApβ contained a more extended conformation. TApβ, therefore, demonstrates a clearer difference in the cyclic peptide conformations when in the cis versus trans form, a feature that may prove beneficial for use with biologically active β‐turn sequences.","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49640302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multiple sclerosis (MS) is an inflammatory demyelinating disease whereby pathology includes multifocal perivascular mononuclear cell infiltration into the central nervous system, oligodendrocyte loss and demyelination, and variable axonal loss. Little is known about the causative agent in MS, but the matrix metalloproteinase (MMP) family of proteolytic enzymes has been implicated in disease progression and resolution. Recent studies revealed that MMP‐2 and/or MMP‐9 are required for an effective T‐cell‐mediated immune response to antigenic stimulation. In the present studies, we used an MMP‐2/MMP‐9 selective triple‐helical peptide inhibitor (THPI) to examine the role of these enzymes in antigen specific T‐cell responses. We found that treatment of murine CD4+ T‐cells with the THPI, followed by CD3/CD28 stimulation of the T‐cell receptor (TCR), resulted in reduced cell proliferation and production of interleukin 2 (IL‐2), interferon gamma (IFN‐γ), and tumor‐necrosis factor alpha (TNF‐α). Application of the THPI in experimental autoimmune encephalomyelitis (EAE), a widely accepted animal model of MS, reduced clinical severity of the disease and weight loss. Splenocytes isolated from THPI‐treated EAE animals had reduced proliferation compared with untreated animals. In an in vitro recall experiment, splenocytes isolated from EAE mice were treated with the THPI, followed by CD3/CD28 stimulation of the TCR. Treated splenocytes had reduced production of IL‐2, IL‐6, IL‐10, IFN‐γ, and TNF‐α compared with untreated splenocytes isolated from EAE mice. Overall, the MMP‐2/MMP‐9‐targeting THPI modulates T‐cell response to antigenic stimulation, including proliferation and immune cell production of specific cytokines, providing insight as to why the THPI is effective in reducing the clinical severity of EAE.
{"title":"Application of a triple‐helical peptide inhibitor of MMP‐2/MMP‐9 to examine T‐cell activation in experimental autoimmune encephalomyelitis","authors":"Lillian C. Onwuha-Ekpete, G. Fields","doi":"10.1002/pep2.24262","DOIUrl":"https://doi.org/10.1002/pep2.24262","url":null,"abstract":"Multiple sclerosis (MS) is an inflammatory demyelinating disease whereby pathology includes multifocal perivascular mononuclear cell infiltration into the central nervous system, oligodendrocyte loss and demyelination, and variable axonal loss. Little is known about the causative agent in MS, but the matrix metalloproteinase (MMP) family of proteolytic enzymes has been implicated in disease progression and resolution. Recent studies revealed that MMP‐2 and/or MMP‐9 are required for an effective T‐cell‐mediated immune response to antigenic stimulation. In the present studies, we used an MMP‐2/MMP‐9 selective triple‐helical peptide inhibitor (THPI) to examine the role of these enzymes in antigen specific T‐cell responses. We found that treatment of murine CD4+ T‐cells with the THPI, followed by CD3/CD28 stimulation of the T‐cell receptor (TCR), resulted in reduced cell proliferation and production of interleukin 2 (IL‐2), interferon gamma (IFN‐γ), and tumor‐necrosis factor alpha (TNF‐α). Application of the THPI in experimental autoimmune encephalomyelitis (EAE), a widely accepted animal model of MS, reduced clinical severity of the disease and weight loss. Splenocytes isolated from THPI‐treated EAE animals had reduced proliferation compared with untreated animals. In an in vitro recall experiment, splenocytes isolated from EAE mice were treated with the THPI, followed by CD3/CD28 stimulation of the TCR. Treated splenocytes had reduced production of IL‐2, IL‐6, IL‐10, IFN‐γ, and TNF‐α compared with untreated splenocytes isolated from EAE mice. Overall, the MMP‐2/MMP‐9‐targeting THPI modulates T‐cell response to antigenic stimulation, including proliferation and immune cell production of specific cytokines, providing insight as to why the THPI is effective in reducing the clinical severity of EAE.","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41504285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To address the growing resistance of Gram‐negative bacteria and enhance the clinical application potential of antimicrobial peptides. In this study, we combined two α‐helical antimicrobial peptides K4 (WRKWRKWRKWRK‐NH2) or K5 (WRKWRKWRKWRKWRK‐NH2) with four traditional antibiotics (gentamicin, rifampicin, ciprofloxacin, and imipenem). Then we explored their potential and mechanism in inhibiting the generation of bacterial resistance. After adding K4 or K5, the tendency to produce resistant bacteria from traditional antibiotics declined significantly. And the obtained antibiotics‐resistant bacteria were further re‐sensitive to their corresponding traditional antibiotics with the addition of K4 or K5. Mostly, the combination showed synergistic or additive antibacterial effects on both the standard strains and the obtained antibiotics‐resistant bacteria, with a much better effect on the latter. Chemical sensitization and the outer membrane permeability experiments demonstrated that K4 and K5 may influence the drug efflux of the tested bacteria, while at the same time improving the outer membrane permeability of the obtained antibiotics‐resistant bacteria to traditional antibiotics by acting as a film breaker. They ultimately eliminated the generation of drug resistance. These results provided an effort that could break Gram‐negative bacteria's resistance.
{"title":"Antimicrobial peptides–antibiotics combination: An effective strategy targeting drug‐resistant Gram‐negative bacteria","authors":"Fangyan Zhang, Chao Zhong, Jia Yao, Jingying Zhang, Tianyue Zhang, Beibei Li, Sanhu Gou, Jingman Ni","doi":"10.1002/pep2.24261","DOIUrl":"https://doi.org/10.1002/pep2.24261","url":null,"abstract":"To address the growing resistance of Gram‐negative bacteria and enhance the clinical application potential of antimicrobial peptides. In this study, we combined two α‐helical antimicrobial peptides K4 (WRKWRKWRKWRK‐NH2) or K5 (WRKWRKWRKWRKWRK‐NH2) with four traditional antibiotics (gentamicin, rifampicin, ciprofloxacin, and imipenem). Then we explored their potential and mechanism in inhibiting the generation of bacterial resistance. After adding K4 or K5, the tendency to produce resistant bacteria from traditional antibiotics declined significantly. And the obtained antibiotics‐resistant bacteria were further re‐sensitive to their corresponding traditional antibiotics with the addition of K4 or K5. Mostly, the combination showed synergistic or additive antibacterial effects on both the standard strains and the obtained antibiotics‐resistant bacteria, with a much better effect on the latter. Chemical sensitization and the outer membrane permeability experiments demonstrated that K4 and K5 may influence the drug efflux of the tested bacteria, while at the same time improving the outer membrane permeability of the obtained antibiotics‐resistant bacteria to traditional antibiotics by acting as a film breaker. They ultimately eliminated the generation of drug resistance. These results provided an effort that could break Gram‐negative bacteria's resistance.","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44622000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cyclic depsipeptides (CDPs) are a family of macrocyclic peptides containing an ester bond(s), generally found as secondary metabolites with bioactivities. Despite the interest of CDPs in drug development, de novo discovery of bioactive CDPs from artificial libraries had been yet challenging due to the lack of their efficient chemical preparation. Our recent report involving ribosomal synthesis of CDPs by means of genetic code reprogramming and S‐to‐O acyl shift chemistry has provided a unique approach for the preparation of CDP libraries and significant potentials that enable for screening of target‐binding species using an in vitro display system. However, even if the selection of binding‐active CDPs were successfully executed, it is unavoidable to chemically prepare a sufficient amount of CDPs for downstream bioassays. Prior to the selection, therefore, it is crucial for us to establish a synthetic methodology of various CDPs using standard solid‐phase chemical synthesis and the S‐to‐O acyl shift as the same key chemistry. Here we report a method of chemical macrolactonization via the S‐to‐S‐to‐O acyl shift, affording CDPs in high yields (~91%). This work links the ribosomal synthesis of CDPs to the chemical synthesis of their active species available from campaigns of the affinity‐based selection, enabling downstream bioassays.
环状沉积肽(CDPs)是一类含有酯键的大环肽，通常是具有生物活性的次生代谢产物。尽管CDPs对药物开发很有兴趣，但由于缺乏有效的化学制备方法，从人工文库中重新发现生物活性的CDPs仍然具有挑战性。我们最近的报告涉及通过遗传密码重编程和S - to - O酰基移位化学方法合成CDP的核糖体，为CDP文库的制备提供了一种独特的方法，并为使用体外展示系统筛选目标结合物种提供了巨大的潜力。然而，即使成功地选择了具有结合活性的CDPs，也不可避免地需要化学制备足够数量的CDPs用于下游的生物测定。因此，在选择之前，对我们来说至关重要的是建立一种使用标准固相化学合成和S - to - O酰基转移作为相同关键化学的各种cdp的合成方法。在这里，我们报告了一种通过S - to - S - to - O酰基转移的化学大内酯化方法，该方法可获得高产率(~91%)的CDPs。这项工作将CDPs的核糖体合成与基于亲和力选择的活性物质的化学合成联系起来，从而实现下游生物测定。
{"title":"Chemical peptide macrolactonization via intramolecular S‐to‐S‐to‐O acyl transfer","authors":"M. Nagano, Yichao Huang, R. Obexer, H. Suga","doi":"10.1002/pep2.24259","DOIUrl":"https://doi.org/10.1002/pep2.24259","url":null,"abstract":"Cyclic depsipeptides (CDPs) are a family of macrocyclic peptides containing an ester bond(s), generally found as secondary metabolites with bioactivities. Despite the interest of CDPs in drug development, de novo discovery of bioactive CDPs from artificial libraries had been yet challenging due to the lack of their efficient chemical preparation. Our recent report involving ribosomal synthesis of CDPs by means of genetic code reprogramming and S‐to‐O acyl shift chemistry has provided a unique approach for the preparation of CDP libraries and significant potentials that enable for screening of target‐binding species using an in vitro display system. However, even if the selection of binding‐active CDPs were successfully executed, it is unavoidable to chemically prepare a sufficient amount of CDPs for downstream bioassays. Prior to the selection, therefore, it is crucial for us to establish a synthetic methodology of various CDPs using standard solid‐phase chemical synthesis and the S‐to‐O acyl shift as the same key chemistry. Here we report a method of chemical macrolactonization via the S‐to‐S‐to‐O acyl shift, affording CDPs in high yields (~91%). This work links the ribosomal synthesis of CDPs to the chemical synthesis of their active species available from campaigns of the affinity‐based selection, enabling downstream bioassays.","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46213356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Improvement in therapeutic efficacy while reducing chemotherapeutic side effects remains a vital objective in synthetic design for cancer treatment. In keeping with the ethos of therapeutic development and inspired by the Warburg effect for augmenting biological activities of the malformin family of cyclic‐peptide natural products, specifically anti‐tumor activity, a β‐glucoside of malformin C has been designed and synthesized utilizing precise glycosylation and solution phase peptide synthesis. We optimized several glycosylation procedures utilizing different donors and acceptors. The overarching goal of this study was to ensure a targeted delivery of a glyco‐malformin C analog through the coupling of D‐glucose moiety; selective transport via glucose transporters (GLUTs) into tumor cells, followed by hydrolysis in the tumor microenvironment releasing the active malformin C a glycon analog. Furthermore, total synthesis of malformin C was carried out with overall improved strategies avoiding unwanted side reactions thus increasing easier purification. We also report on an improved solid phase peptide synthesis protocol for malformin A1.
{"title":"Synthesis of malformin‐A1, C, a glycan, and an aglycon analog: Potential scaffolds for targeted cancer therapy","authors":"F. Hossain, S. Nishat, P. Andreana","doi":"10.1002/pep2.24260","DOIUrl":"https://doi.org/10.1002/pep2.24260","url":null,"abstract":"Improvement in therapeutic efficacy while reducing chemotherapeutic side effects remains a vital objective in synthetic design for cancer treatment. In keeping with the ethos of therapeutic development and inspired by the Warburg effect for augmenting biological activities of the malformin family of cyclic‐peptide natural products, specifically anti‐tumor activity, a β‐glucoside of malformin C has been designed and synthesized utilizing precise glycosylation and solution phase peptide synthesis. We optimized several glycosylation procedures utilizing different donors and acceptors. The overarching goal of this study was to ensure a targeted delivery of a glyco‐malformin C analog through the coupling of D‐glucose moiety; selective transport via glucose transporters (GLUTs) into tumor cells, followed by hydrolysis in the tumor microenvironment releasing the active malformin C a glycon analog. Furthermore, total synthesis of malformin C was carried out with overall improved strategies avoiding unwanted side reactions thus increasing easier purification. We also report on an improved solid phase peptide synthesis protocol for malformin A1.","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42836008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Our previous study shows that the peptide consisting of 29 residues at positions 354–382 of zebrafish AP‐2 complex subunit mu‐A is an antimicrobial peptide (AMP) capable of inhibiting the growth of Escherichia coli and Staphylococcus aureus. Sequence analysis revealed that the N‐terminal 10 amino acids (designated AP10) of the peptide were highly conserved from nematode to humans. On this basis, we designed two AP10 analogs, AP10R and AP10W, by substituting the amino acids at selected positions of AP10 with tryptophan (W), isoleucine (I), and arginine (R). Both AP10 and AP10R as well as AP10W were found to possess the common features of AMPs: a high hydrophobic ratio, a net positive charge, and amphipathicity. Antibacterial activity assay showed that AP10W exhibited the strongest antimicrobial activity against Gram‐negative and Gram‐positive bacteria including MDR bacteria (with MICs ranging from 20 to 25 μg/ml) among the three peptides. In addition, AP10W was able to bind to lipopolysaccharide (LPS), lipoteichoic acid (LTA), and peptidoglycan (PGN), cause depolarization of the bacterial plasma membrane, and stimulate intracellular reactive oxygen species (ROS) production, suggesting it executes antibacterial activity by a combined action of destabilization/destruction of bacterial cell wall through interaction with LPS, LTA, and PGN, disturbance of the usually polarized membrane through depolarization, and apoptosis/necrosis through intracellular ROS production. Importantly, AP10W is not toxic to mammalian cells, and shows tolerance to serum, salt, and pH variation though it is heat labile. These together suggest that AP10W is a promising template for future development of novel peptide antibiotics against MDR bacteria.
{"title":"A short peptide derived from zebrafish AP‐2 complex subunit mu‐A AP2M1A354–382 has antimicrobial activity against multi‐drug resistant bacteria","authors":"Yi Gong, Haoyi Li, Fei Wu, Xiangmin Zhang, Yucong Zhou, Shicui Zhang","doi":"10.1002/pep2.24258","DOIUrl":"https://doi.org/10.1002/pep2.24258","url":null,"abstract":"Our previous study shows that the peptide consisting of 29 residues at positions 354–382 of zebrafish AP‐2 complex subunit mu‐A is an antimicrobial peptide (AMP) capable of inhibiting the growth of Escherichia coli and Staphylococcus aureus. Sequence analysis revealed that the N‐terminal 10 amino acids (designated AP10) of the peptide were highly conserved from nematode to humans. On this basis, we designed two AP10 analogs, AP10R and AP10W, by substituting the amino acids at selected positions of AP10 with tryptophan (W), isoleucine (I), and arginine (R). Both AP10 and AP10R as well as AP10W were found to possess the common features of AMPs: a high hydrophobic ratio, a net positive charge, and amphipathicity. Antibacterial activity assay showed that AP10W exhibited the strongest antimicrobial activity against Gram‐negative and Gram‐positive bacteria including MDR bacteria (with MICs ranging from 20 to 25 μg/ml) among the three peptides. In addition, AP10W was able to bind to lipopolysaccharide (LPS), lipoteichoic acid (LTA), and peptidoglycan (PGN), cause depolarization of the bacterial plasma membrane, and stimulate intracellular reactive oxygen species (ROS) production, suggesting it executes antibacterial activity by a combined action of destabilization/destruction of bacterial cell wall through interaction with LPS, LTA, and PGN, disturbance of the usually polarized membrane through depolarization, and apoptosis/necrosis through intracellular ROS production. Importantly, AP10W is not toxic to mammalian cells, and shows tolerance to serum, salt, and pH variation though it is heat labile. These together suggest that AP10W is a promising template for future development of novel peptide antibiotics against MDR bacteria.","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46276253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Cheung, H. Chow, Can Li, P. Blasco, Kaichao Chen, Shengbao Chen, Xuechen Li
Herein, we report the synthesis of a daptomycin thiolactone analogue via the MeDbz‐linker based on resin self‐cleaving macrocyclization pathway. A detailed investigation of the reaction conditions is reported, including the variation of the cyclization buffer, temperature, concentration, and reaction time. Severe hydrolysis was observed under most of the conditions screened, presumably due to the low reactivity of (2R,3R)‐β‐methylcysteine (thioThr) used. Eventually, pyridine/acetic acid buffer was identified as the most viable solvent system to afford the hydrolysis‐free product. We perceive that this optimized protocol will enable the synthesis of other challenging thiolactone peptides, possibly those involving thioThr or penicillamine.
{"title":"Synthesis of a daptomycin thiolactone analogue via the MeDbz‐linker‐based cyclative‐cleavage approach","authors":"C. Cheung, H. Chow, Can Li, P. Blasco, Kaichao Chen, Shengbao Chen, Xuechen Li","doi":"10.1002/pep2.24255","DOIUrl":"https://doi.org/10.1002/pep2.24255","url":null,"abstract":"Herein, we report the synthesis of a daptomycin thiolactone analogue via the MeDbz‐linker based on resin self‐cleaving macrocyclization pathway. A detailed investigation of the reaction conditions is reported, including the variation of the cyclization buffer, temperature, concentration, and reaction time. Severe hydrolysis was observed under most of the conditions screened, presumably due to the low reactivity of (2R,3R)‐β‐methylcysteine (thioThr) used. Eventually, pyridine/acetic acid buffer was identified as the most viable solvent system to afford the hydrolysis‐free product. We perceive that this optimized protocol will enable the synthesis of other challenging thiolactone peptides, possibly those involving thioThr or penicillamine.","PeriodicalId":19825,"journal":{"name":"Peptide Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48594271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号