• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Infection and immunity >Cysteine-Scanning Mutagenesis Supports the Importance of Clostridium perfringens Enterotoxin Amino Acids 80 to 106 for Membrane Insertion and Pore Formation
【24h】

Cysteine-Scanning Mutagenesis Supports the Importance of Clostridium perfringens Enterotoxin Amino Acids 80 to 106 for Membrane Insertion and Pore Formation

机译：半胱氨酸扫描诱变支持产气荚膜梭菌肠毒素氨基酸80至106对于膜插入和孔形成的重要性。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Clostridium perfringens enterotoxin (CPE) causes the gastrointestinal symptoms of the second most common bacterial food-borne illness. Previous studies suggested that a region named TM1, which has amphipathic characteristics and spans from amino acids 81 to 106 of the native CPE protein, forms a β-hairpin involved in β-barrel pore formation. To further explore the potential role of TM1 in pore formation, the single Cys naturally present in CPE at residue 186 was first altered to alanine by mutagenesis; the resultant rCPE variant, named C186A, was shown to retain cytotoxic properties. Cys-scanning mutagenesis was then performed in which individual Cys mutations were introduced into each TM1 residue of the C186A variant. When those Cys variants were characterized, three variants were identified that exhibit reduced cytotoxicity despite possessing binding and oligomerization abilities similar to those of the C186A variant from which they were derived. Pronase challenge experiments suggested that the reduced cytotoxicity of those two Cys variants, i.e., the F91C and F95C variants, which model to the tip of the β-hairpin, was attributable to a lessened ability of these variants to insert into membranes after oligomerization. In contrast, another Cys variant, i.e., the G103C variant, with impaired cytotoxicity apparently inserted into membranes after oligomerization but could not form a pore with a fully functional channel. Collectively, these results support the TM1 region forming a β-hairpin as an important step in CPE insertion and pore formation. Furthermore, this work identifies the first amino acid residues specifically involved in those two steps in CPE action.
机译：产气荚膜梭菌肠毒素（CPE）引起第二大最常见的细菌性食源性疾病的胃肠道症状。先前的研究表明，一个名为TM1的区域具有两亲性特征，其跨域为天然CPE蛋白的第81至106位氨基酸，形成了一个与β-桶孔形成有关的β-发夹结构。为了进一步探索TM1在孔形成中的潜在作用，首先通过诱变将天然存在于CPE中残基186的单个Cys转变为丙氨酸。结果表明，所得的rCPE变体名为C186A，保留了细胞毒性。然后进行Cys扫描诱变，其中将单个Cys突变引入C186A变体的每个TM1残基中。当表征那些Cys变异体时，鉴定出三个变异体，尽管它们具有与衍生自它们的C186A变异体相似的结合和寡聚能力，但它们显示出降低的细胞毒性。 pronase攻击实验表明，这两种Cys变体（即以β-发夹末端为模型的F91C和F95C变体）细胞毒性降低，是由于这些变体寡聚后插入膜的能力降低。相反，具有低细胞毒性的另一半胱氨酸变体，即G103C变体，在低聚后显然插入了膜中，但不能形成具有完全功能性通道的孔。总之，这些结果支持形成β-发夹的TM1区域作为CPE插入和孔形成中的重要步骤。此外，这项工作确定了在CPE作用中这两个步骤中特别涉及的第一个氨基酸残基。

著录项

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号