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Crystal structure of a membrane-embedded H~+-translocating pyrophosphatase

机译:膜包埋的H〜+易位焦磷酸酶的晶体结构

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摘要

H~+-translocating pyrophosphatases (H~+-PPases) are active proton transporters that establish a proton gradient across the endomembrane by means of pyrophosphate (PPi) hydrolysis~(1,2). H~+-PPases are found primarily as homodimers in the vacuolar membrane of plants and the plasma membrane of several protozoa and prokaryotes~(2,3). The three-dimensional structure and detailed mechanisms underlying the enzymatic and proton translocation reactions of H~+-PPases are unclear. Here we report the crystal structure of a Vigna radiata H~+-PPase (VrH~+-PPase) in complex with a non-hydrolysable substrate analogue, imidodiphosphate (IDP), at 2.35 A resolution. Each VrH~+-PPase subunit consists of an integral membrane domain formed by 16 transmembrane helices. IDP is bound in the cytosolic region of each subunit and trapped by numerous charged residues and five Mg~(2+) ions. A previously undescribed proton translocation pathway is formed by six core transmembrane helices. Proton pumping can be initialized by PP_i hydrolysis, and H~+ is then transported into the vacuolar lumen through a pathway consisting of Arg 242, Asp 294, Lys 742 and Glu 301. We propose a working model of the mechanism for the coupling between proton pumping and PP_i hydrolysis by H~+-PPases.%两种类型的质子泵输蛋白,即“液泡H~+-ATPrn酶”和“H~+-转位焦磷酸酶”(H~+-Ppases),共rn存于植物液泡膜上,将ATP和焦磷酸盐(分别)rn用作质子转位的能源。虽然“液泡H~+-ATP酶”rn已被进行了非常广泛的研究,但H~+-Ppases的rn三维结构及其水解和质子转位反应的详细机rn制却不清楚。这篇论文报告了在一个“非可水rn解基质类似物”存在时的H~+-Ppases的晶体结rn构。一个不同寻常的质子转位通道由六个核心rn跨膜螺旋体形成。本文作者们提出了一个关于rn质子泵输和焦磷酸酶水解是怎样耦合在一起的rn模型。
机译:H〜-易位焦磷酸酶(H〜+ -PPases)是一种活性质子转运蛋白,通过焦磷酸(PPi)水解〜(1,2)在整个膜上建立质子梯度。 H + -PPases主要在植物的液泡膜和几种原生动物和原核生物的质膜中被发现为同二聚体(2,3)。 H + -PPases的酶和质子易位反应的三维结构和详细的机制尚不清楚。在这里,我们以2.35 A的分辨率报告了与不可水解的底物类似物亚胺基二磷酸酯(IDP)配合使用的Vigna radiata H〜+ -PPase(VrH〜+ -PPase)的晶体结构。每个VrH〜+ -PPase亚基由16个跨膜螺旋形成的完整膜结构域组成。 IDP结合在每个亚基的胞质区域,并被大量带电荷的残基和五个Mg〜(2+)离子捕获。先前未描述的质子易位途径是由六个核心跨膜螺旋形成的。质子泵送可以通过PP_i水解来初始化,然后H〜+通过Arg 242,Asp 294,Lys 742和Glu 301组成的途径转运到液泡腔中。我们提出了质子之间耦合机理的工作模型。 %类型类型的质子泵输蛋白,即“液泡H〜+ -ATPrn酶”和“ H〜+-转位焦磷酸酶”(H〜+ -Ppases) ,“共泡存于植物液泡膜上,将ATP和焦磷酸盐(分别)rn利用质子转位的能源。虽然”液泡H〜+ -ATP酶” rn已被进行了非常广泛的研究,但H 〜+ -Ppases的rn三维结构及其嵌入和质子转位反应的详细机rn制却清晰。这篇论文报告了在一个“非可水rn解分解类似物”存在时的H〜+ -Ppases一个不同寻常的质子转位通道由六个核心rn跨膜螺旋体形成。此处作者们提出了一个关于rn质子泵输和焦磷酸酶分解是怎样转化在一起的rn模型的。

著录项

  • 来源
    《Nature》 |2012年第7394期|p.399-403C5|共6页
  • 作者单位

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

    Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan;

    Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan;

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

    Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan;

  • 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);
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