Enzymes are known to adopt various conformations at different points along their catalytic cycles. Here, we present a comprehensive analysis of 15 isomorphous, high resolution crystal structures of the enzyme phosphoglucomutase from the bacterium Xanthomonas citri. The protein was captured in distinct states critical to function, including enzyme-substrate, enzyme-product, and enzyme-intermediate complexes. Key residues in ligand recognition and regions undergoing conformational change are identified and correlated with the various steps of the catalytic reaction. In addition, we use principal component analysis to examine various subsets of these structures with two goals: (1) identifying sites of conformational heterogeneity through a comparison of room temperature and cryogenic structures of the apo-enzyme and (2) a priori clustering of the enzyme-ligand complexes into functionally related groups, showing sensitivity of this method to structural features difficult to detect by traditional methods. This study captures, in a single system, the structural basis of diverse substrate recognition, the subtle impact of covalent modification, and the role of ligand-induced conformational change in this representative enzyme of the α-D-phosphohexomutase superfamily.

中文翻译：

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磷酸己糖变位酶酶促反应的结构和动力学描述。

众所周知，酶在其催化循环的不同点上会采用不同的构象。在这里，我们对来自柑橘黄单胞菌的磷酸葡萄糖变位酶的 15 种同形、高分辨率晶体结构进行了全面分析。该蛋白质以对功能至关重要的不同状态被捕获，包括酶-底物、酶-产物和酶-中间体复合物。配体识别中的关键残基和经历构象变化的区域被识别并与催化反应的各个步骤相关联。此外，我们使用主成分分析来检查这些结构的各种子集，有两个目标：（1）通过比较脱辅基酶的室温和低温结构来识别构象异质性位点，以及（2）先验聚类酶-配体复合物转化为功能相关的基团，显示出该方法对传统方法难以检测的结构特征的敏感性。这项研究在单一系统中捕获了不同底物识别的结构基础、共价修饰的微妙影响以及配体诱导的构象变化在 α-D-磷酸己糖变位酶超家族的这种代表性酶中的作用。