Crystal structures of pyruvate phosphate dikinase from maize revealed an alternative conformation in the swiveling-domain motion.
Crystal structures of pyruvate phosphate dikinase from maize revealed an alternative conformation in the swiveling-domain motion.
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DOI：
10.1021/bi0484522
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发表时间：
2005-02
期刊：
影响因子：
2.9
通讯作者：
T. Nakanishi;T. Nakatsu;M. Matsuoka;K. Sakata;H. Kato
中科院分区：
文献类型：
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作者：
T. Nakanishi;T. Nakatsu;M. Matsuoka;K. Sakata;H. Kato
丙酮酸磷酸二激酶（PPDK）可逆地催化ATP、磷酸和丙酮酸分别转化为AMP、焦磷酸和磷酸烯醇丙酮酸（PEP）。由于核苷酸结合位点（在N-末端结构域中）和丙酮酸/PEP结合位点（在C-末端结构域中）相隔约45 A，因此已经提出称为中心结构域的中间结构域在这些远程结构域之间旋转以转移磷酸。然而，没有直接的结构证据的旋转中心域已被发现。在这项研究中，玉米PPDK的晶体结构与无PEP已确定在2.3分辨率。这些结构表明，中央结构域位于丙酮酸/PEP结合C末端结构域附近，与来自共生梭菌的PPDK相反，其中中央结构域位于核苷酸结合N末端结构域附近。玉米和C. symbiosum PPDK证明了中心域的旋转运动包括至少92度的旋转和0.5A的平移。通过比较有和没有PEP的玉米PPDK结构，我们已经阐明了PEP的C-末端结构域的结合模式和诱导的中央结构域的构象变化。
Pyruvate phosphate dikinase (PPDK) reversibly catalyzes the conversion of ATP, phosphate, and pyruvate into AMP, pyrophosphate, and phosphoenolpyruvate (PEP), respectively. Since the nucleotide binding site (in the N-terminal domain) and the pyruvate/PEP binding site (in the C-terminal domain) are separated by approximately 45 A, it has been proposed that an intermediary domain, called the central domain, swivels between these remote domains to transfer the phosphate. However, no direct structural evidence for the swiveling central domain has been found. In this study, the crystal structures of maize PPDK with and without PEP have been determined at 2.3 A resolution. These structures revealed that the central domain is located near the pyruvate/PEP binding C-terminal domain, in contrast to the PPDK from Clostridium symbiosum, wherein the central domain is located near the nucleotide-binding N-terminal domain. Structural comparisons between the maize and C. symbiosum PPDKs demonstrated that the swiveling motion of the central domain consists of a rotation of at least 92 degrees and a translation of 0.5 A. By comparing the maize PPDK structures with and without PEP, we have elucidated the mode of binding of PEP to the C-terminal domain and the induced conformational changes in the central domain.