Insights into nucleotide signal transduction in nitrogenase: Protein with MgADP bound
Insights into nucleotide signal transduction in nitrogenase: Protein with MgADP bound
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DOI：
10.1021/bi001705g
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发表时间：
2000-12-05
期刊：
影响因子：
2.9
通讯作者：
Peters, JW
中科院分区：
文献类型：
--
作者：
Jang, SB;Seefeldt, LC;Peters, JW
将三磷酸核苷结合和水解的能量与构象变化耦合是许多具有不同细胞功能的蛋白质的常见机制，包括那些涉及 DNA 复制、蛋白质合成和细胞分化的蛋白质。这类蛋白质的独特之处在于固氮酶的二聚铁蛋白成分，其中 MgATP 的结合和水解控制分子间电子转移和氮还原为氨。在此介绍的工作中，捕获了固氮酶 Fe 蛋白的 MgADP 结合（或“关闭”）构象状态，并呈现了 2.15 埃分辨率的 X 射线晶体结构。本文描述的结构揭示了从核苷酸结合位点进行长距离通信以控制与 MoFe 蛋白质组分缔合的亲和力的可能机制。两条途径，称为开关 I 和 II，似乎是该核苷酸信号转导机制的组成部分。此外，该结构为Fe蛋白结合核苷酸时观察到的[4Fe-4S]簇生物物理性质的变化提供了基础。 MgADP 结合的 Fe 蛋白的结构为了解核苷酸相互作用和复合物形成在定义构象状态（固氮酶催化的关键）方面各自的贡献提供了重要的见解。
Coupling the energy of nucleoside triphosphate binding and hydrolysis to conformational changes is a common mechanism for a number of proteins with disparate cellular functions, including those involved in DNA replication, protein synthesis, and cell differentiation. Unique to this class of proteins is the dimeric Fe protein component of nitrogenase in which the binding and hydrolysis of MgATP controls intermolecular electron transfer and reduction of nitrogen to ammonia. In the work presented here, the MgADP-bound (or "off") conformational state of the nitrogenase Fe protein has been captured and a 2.15 Angstrom resolution X-ray crystal structure is presented. The structure described herein reveals likely mechanisms for long-range communication from the nucleotide-binding sites for controlling the affinity of association with the MoFe protein component. Two pathways, termed switches I and II, appear to be integral to this nucleotide signal transduction mechanism. In addition, the structure provides the basis for the changes in the biophysical properties of the [4Fe-4S] cluster observed when Fe protein binds nucleotides. The structure of the MgADP-bound Fe protein provides important insights into the respective contributions of nucleotide interaction and complex formation in defining the conformational states that are the keys to nitrogenase catalysis.