...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >Multidrug Efflux Pump MdtBC of Escherichia coli Is Active Only as a B2C Heterotrimer
【24h】

Multidrug Efflux Pump MdtBC of Escherichia coli Is Active Only as a B2C Heterotrimer

机译：大肠杆菌的多药外排泵MdtBC仅作为B2C异三聚体起作用

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

摘要

RND (resistance-nodulation-division) family transporters in Gram-negative bacteria frequently pump out a wide range of inhibitors and often contribute to multidrug resistance to antibiotics and biocides. An archetypal RND pump of Escherichia coli, AcrB, is known to exist as a homotrimer, and this construction is essential for drug pumping through the functionally rotating mechanism. MdtBC, however, appears different because two pump genes coexist within a single operon, and genetic deletion data suggest that both pumps must be expressed in order for the drug efflux to occur. We have expressed the corresponding genes, with one of them in a His-tagged form. Copurification of MdtB and MdtC under these conditions showed that they form a complex, with an average stoichiometry of 2:1. Unequivocal evidence that only the trimer containing two B protomers and one C protomer is active was obtained by expressing all possible combinations of B and C in covalently linked forms. Finally, conversion into alanine of the residues, known to form a proton translocation pathway in AcrB, inactivated transport only when made in MdtB, not when made in MdtC, a result suggesting that MdtC plays a different role not directly involved in drug binding and extrusion.
机译：革兰氏阴性细菌中的RND（耐药性结节分支）家族转运蛋白经常会抽出多种抑制剂，并经常对抗生素和杀生物剂产生多重耐药性。已知大肠埃希氏菌的原型RND泵AcrB以同源三聚体的形式存在，这种结构对于通过功能性旋转机制泵送药物至关重要。但是，MdtBC看起来有所不同，因为两个泵基因共存于一个操纵子中，遗传缺失数据表明必须同时表达两个泵才能发生药物外排。我们已经表达了相应的基因，其中一个具有His标签形式。在这些条件下对MdtB和MdtC的共纯化表明它们形成复合物，平均化学计量比为2：1。通过以共价连接的形式表达B和C的所有可能组合，获得了仅包含两个B Protomer和一个C Protomer的三聚体有效的明确证据。最后，已知在AcrB中形成质子易位途径的残基转化为丙氨酸，仅当在MdtB中制造时才灭活运输，而在MdtC中制造时才灭活，结果表明MdtC发挥了不同的作用，并不直接参与药物结合和挤出。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 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