• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Nature >Mechanism of substrate recognition and transport by an amino acid antiporter
【24h】

Mechanism of substrate recognition and transport by an amino acid antiporter

机译：氨基酸反转运蛋白对底物的识别和转运机制

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In extremely acidic environments, enteric bacteria such as Escherichia coli rely on the amino acid antiporter AdiC to expel protons by exchanging intracellular agmatine (Agm~(2+)) for extracellular arginine (Arg~+). AdiC is a representative member of the amino acid-polyamine-organocation (APC) superfamily of membrane transporters. The structure of substrate-free AdiC revealed a homodimeric assembly, with each protomer containing 12 transmembrane segments and existing in an outward-open conformation. The overall folding of AdiC is similar to that of the Na~+-coupled symporters. Despite these advances, it remains unclear how the substrate (arginine or agmatine) is recognized and transported by AdiC. Here we report the crystal structure of an E. coli AdiC variant bound to Arg at 3.0 A resolution. The positively charged Arg is enclosed in an acidic binding chamber, with the head groups of Arg hydrogen-bonded to main chain atoms of AdiC and the aliphatic portion of Arg stacked by hydro-phobic side chains of highly conserved residues. Arg binding induces pronounced structural rearrangement in transmembrane helix 6 (TM6) and, to a lesser extent, TM2 and TM10, resulting in an occluded conformation. Structural analysis identified three potential gates, involving four aromatic residues and Glu 208, which may work in concert to differentially regulate the upload and release of Arg and Agm.
机译：在极端酸性的环境中，肠细菌（例如大肠杆菌）通过将细胞内的胍丁胺（Agm〜（2+））交换为细胞外的精氨酸（Arg〜+），依靠氨基酸逆向转运蛋白AdiC排出质子。 AdiC是膜转运蛋白的氨基酸-多胺-有机（APC）超家族的代表成员。无底物的AdiC的结构揭示了一个同二聚体组装，每个protomer包含12个跨膜片段，并以向外开放的构型存在。 AdiC的整体折叠与Na〜+偶联的同向转运子相似。尽管取得了这些进展，但仍不清楚AdiC如何识别和运输底物（精氨酸或胍丁胺）。在这里，我们报告了以3.0 A的分辨率与Arg结合的大肠杆菌AdiC变体的晶体结构。带正电荷的Arg被封闭在一个酸性结合室中，其中Arg的头基氢键合到AdiC的主链原子上，而Arg的脂族部分则通过高度保守的残基的疏水侧链堆叠。 Arg结合在跨膜螺旋6（TM6）中引起明显的结构重排，并在较小程度上诱导TM2和TM10，导致封闭的构象。结构分析确定了三个潜在的门，涉及四个芳族残基和Glu 208，它们可以协同作用以差异调节Arg和Agm的上载和释放。

著录项

  • 来源
    《Nature》 |2010年第7282期|828-832|共5页
  • 作者

    Xiang Gao; Lijun Zhou; Xuyao Jiao; Feiran Lu; Chuangye Yan; Xin Zeng; Jiawei Wang; Yigong Shi;

  • 作者单位

    Ministry of Education Protein Science Laboratory, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;

    State Key Laboratory of Biomembrane and Membrane Biotechnology, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;

    State Key Laboratory of Biomembrane and Membrane Biotechnology, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China School of Life Sciences, Shandong University, Jinan, Shandong 250100, China;

    State Key Laboratory of Biomembrane and Membrane Biotechnology, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;

    State Key Laboratory of Biomembrane and Membrane Biotechnology, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;

    Ministry of Education Protein Science Laboratory, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;

    State Key Laboratory of Biomembrane and Membrane Biotechnology, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;

    Ministry of Education Protein Science Laboratory, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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