...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>European Journal of Cell Biology: Journal of Deutsche Gesellschaft fur Elektronenmikroskopie: Journal of Deutsche Gesellschaft fur Zellbiologie >The KdpFABC complex from Escherichia coli: A chimeric K+ transporter merging ion pumps with ion channels
【24h】

The KdpFABC complex from Escherichia coli: A chimeric K+ transporter merging ion pumps with ion channels

机译：大肠杆菌的KdpFABC复合物：融合离子泵和离子通道的嵌合K +转运蛋白

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

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

摘要

The KdpFABC complex represents a multi-subunit ATP-driven potassium pump, which is only found in bacteria and archaea. Based on the properties of the ATP-hydrolyzing subunit (KdpB) the transporter has been classified as a type IA P-type ATPase. However, structural and functional properties of the remaining subunits clearly show homologies to members of the potassium channel as well as the ABC transporter family, thus rendering the KdpFABC complex to represent an inimitable chimera of ion pumps and ion channels. Accordingly, this striking juxtaposition entails special features of KdpFABC with respect to typical members of each of the transporter families, involving not only the concepts but also the structures of ion channels and ion pumps. For example, the sites of ATP hydrolysis and substrate transport are spatially separated on two different polypeptides, which, in turn, leads to a unique coupling mechanism. During catalysis, the KdpFABC complex cycles between two main conformational states, each of which comprises different structural properties together with different binding affinities for both ATP and the transport substrate. These structural configurations have recently been directly visualized in the working enzyme. Translocation of potassium is mediated by the KdpA subunit, which comprises structural as well as functional homologies to potassium channels of the MPM-type. The KdpC subunit participates in the binding of ATP, thus acting as a catalytic chaperone, which increases the ATP binding affinity of the KdpB subunit via a mechanism typical of nucleotide binding in ABC transporters
机译：KdpFABC复合物代表由ATP驱动的多亚基钾泵，仅在细菌和古细菌中发现。根据ATP水解亚基（KdpB）的性质，转运蛋白已被分类为IA P型ATPase。但是，其余亚基的结构和功能特性清楚地表明与钾离子通道成员以及ABC转运蛋白家族同源，从而使KdpFABC复合物代表离子泵和离子通道的独特嵌合体。因此，这种惊人的并置使得KdpFABC相对于每个转运蛋白家族的典型成员具有特殊的特征，不仅涉及离子通道和离子泵的概念，还涉及其结构。例如，ATP水解和底物转运的位点在两个不同的多肽上在空间上分开，这又导致了独特的偶联机制。在催化过程中，KdpFABC络合物在两个主要构象状态之间循环，每个状态都包含不同的结构特性以及对ATP和转运底物的不同结合亲和力。这些结构构型最近已在工作酶中直接显现。钾的转运由KdpA亚基介导，该亚基包含与MPM型钾通道的结构和功能同源性。 KdpC亚基参与ATP的结合，因此起催化分子伴侣的作用，通过ABC转运蛋白中典型的核苷酸结合机制提高KdpB亚基的ATP结合亲和力。

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