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首页> 外文学位 >Studies in the antimicrobial mechanism of the lantibiotics nisin and sublancin, and, A Bacillus subtilis 168 expression system that displays the lantibiotic antimicrobial peptide sublancin on the cell surface.
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Studies in the antimicrobial mechanism of the lantibiotics nisin and sublancin, and, A Bacillus subtilis 168 expression system that displays the lantibiotic antimicrobial peptide sublancin on the cell surface.

机译：研究了羊毛硫抗生素乳酸链球菌素和潜蛋白的抗菌机制，以及枯草芽孢杆菌168表达系统，该表达系统在细胞表面显示羊毛硫抗生素抗菌肽潜蛋白。

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摘要

In this work, the ability of nisin to bind to a variety of biological target structures was explored. Nisin was demonstrated as having the ability to bind non-ionic cellulose under mildly alkaline conditions (pH 8.0).;The dependence of binding on pH is consistent with nisin's role in autoregulation of its own biosynthesis and also may contribute its ability to provide a defense against its ecological-niche competitors. This unique ability to bind cellulose served as a potential new means for purification of nisin, and it was demonstrated that non-ionic cellulose could be used to prepare highly purified nisin from a culture of Lactococcus lactis 11454.;The possibility that the antimicrobial activity of nisin involves its ability to recognize specific polypeptide structural motifs was explored. Nisin was allowed to select for specific binding motifs from random 7-mer and 12-mer peptide libraries displayed on the surface of M13 bacteriophage. Nisin selected strongly for a motif having the consensus sequence PPS(T/S)XKL. The motif shared strong homology to the active-site motifs found in penicillin-binding proteins, which are membrane-bound enzymes involved in cell wall biosynthesis. The identification of this motif is consistent with nisin's ability to inhibit cell wall biosynthesis and suggests that the mechanism of nisin action includes its specific binding to the active-sites of penicillin-binding proteins, thereby inhibiting their activity.;A system was developed to display the lantibiotic sublancin on the surface of its Bacillus subtilis 168 producer cell. The displayed sublancin was found to be accessible by antibodies which are exposed to the producer cell surface. It was further demonstrated that this interaction allowed for cells that displayed the sublancin peptide could be purified away from cells that did not. This provides the basis of isolation of ligand-specific sublancin analogues from a combinatorial display library.;The antimicrobial mechanism of the lantibiotic sublancin was explored by identifying a biological target from Bacillus subtilis 168. A C-terminal 6xHis-tag was fused to sublancin by mutagenesis of the sublancin structural gene. After analysis of the tandem MS/MS spectra by the SEQUEST algorithm, the protein was identified as elongation factor Tu, which is a component of the protein synthetic machinery. The ability of sublancin to specifically bind to this protein suggests that its mechanism of action involves the inhibition of protein biosynthesis. (Abstract shortened by UMI.)
机译：在这项工作中，探索了乳链菌肽结合多种生物靶标结构的能力。乳链菌肽被证明具有在弱碱性条件下（pH 8.0）结合非离子纤维素的能力;结合对pH的依赖性与乳链菌肽在自身调节自身生物合成中的作用相一致，也可能有助于其提供防御能力反对其生态位竞争者。这种独特的结合纤维素的能力是纯化乳链菌肽的潜在新手段，并且证明非离子纤维素可用于从乳酸乳球菌11454的培养物中制备高度纯化的乳链菌肽。乳链菌肽涉及其识别特定多肽结构基序的能力。使乳链菌肽从展示在M13噬菌体表面上的随机的7聚体和12聚体肽文库中选择特异性结合基序。乳链菌肽强烈选择具有共有序列PPS（T / S）XKL的基序。该基序与在青霉素结合蛋白中发现的活性位点基序具有强烈的同源性，青霉素结合蛋白是参与细胞壁生物合成的膜结合酶。该基序的鉴定与乳链菌肽抑制细胞壁生物合成的能力是一致的，并且表明乳链菌肽作用的机制包括其与青霉素结合蛋白的活性位点的特异性结合，从而抑制其活性。枯草芽孢杆菌168生产细胞表面上的羊毛硫抗生素sublancin。发现展示的sublancin可被暴露于生产细胞表面的抗体所接近。进一步证明，这种相互作用使得展示亚lancin肽的细胞可以从没有纯化出亚兰蛋白肽的细胞中纯化出来。这提供了从组合展示库中分离配体特异性亚lancin类似物的基础。通过鉴定枯草芽孢杆菌168的生物学靶标，探索了羊毛硫抗生素亚lancin的抗菌机制。C末端的6xHis标签通过sub融合融合到sublancin上。 sublancin结构基因的诱变。通过SEQUEST算法分析串联MS / MS光谱后，该蛋白质被鉴定为延伸因子Tu，它是蛋白质合成机器的组成部分。 Sublancin特异性结合该蛋白质的能力表明其作用机理涉及蛋白质生物合成的抑制。 （摘要由UMI缩短。）

著录项

  • 作者

    Villaruz, Amer Emilio Cosca.;

  • 作者单位

    University of Maryland, College Park.;

  • 授予单位 University of Maryland, College Park.;
  • 学科 Chemistry Biochemistry.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 158 p.
  • 总页数 158
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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