Crystal structure and molecular mechanism of an aspartate/glutamate racemase from Escherichia coli O157
Crystal structure and molecular mechanism of an aspartate/glutamate racemase from Escherichia coli O157
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DOI：
10.1002/1873-3468.12148
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发表时间：
2016-04
期刊：
影响因子：
3.5
通讯作者：
Xiuhua Liu;F. Gao;Yinliang Ma;Shuang Liu;Yaqi Cui;Zenglin Yuan;X. Kang
中科院分区：
文献类型：
--
作者：
Xiuhua Liu;F. Gao;Yinliang Ma;Shuang Liu;Yaqi Cui;Zenglin Yuan;X. Kang
来自病原菌大肠杆菌O157的天冬氨酸/谷氨酸消旋酶EcL‐DER对天冬氨酸和谷氨酸具有消旋酶活性。本研究报道了载子- EcL - DER、EcL - DER - 1 -天冬氨酸和EcL - DER - d -天冬氨酸配合物的晶体结构。EcL - DER结构包含两个结构域，在活性位点形成伪镜像对称。在活性位点存在由Thr83和Cys197组成的独特催化对。l - Asp和d - Asp在活性位点的特征构象为EcL - DER的外消旋机理提供了直接的结构证据。此外，催化对的多样性表明，不依赖PLP的氨基酸外消旋酶采用多种催化机制，并被划分为不同的亚群。
EcL‐DER, the aspartate/glutamate racemase from the pathogen Escherichia coli O157, exhibits racemase activity for l‐aspartate and l‐glutamate. This study reports the crystal structures of apo‐EcL‐DER, the EcL‐DER‐l‐aspartate and the EcL‐DER‐d‐aspartate complexes. The EcL‐DER structure contains two domains, forming pseudo‐mirror symmetry in the active site. A unique catalytic pair consisting of Thr83 and Cys197 exists in the active site. The characteristic conformations of l‐Asp and d‐Asp in the active site provide a straight structural evidence for the racemization mechanism of EcL‐DER. In addition, the diversity of catalytic pairs implies that PLP‐independent amino acid racemases adopt various catalytic mechanisms and are classified into different subgroups.