Structural Basis of the Substrate Specificity of Bifunctional Isocitrate Dehydrogenase Kinase/Phosphatase

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• 作者：Susan P. Yates ; Thomas E. Edwards ; Cassie M. Bryan ; Adam J. Stein ; Wesley C. Van Voorhis ; Peter J. Myler ; Lance J. Stewart ; Jimin Zheng ; Zongchao Jia
• 刊名：Biochemistry
• 出版年：2011
• 出版时间：September 27, 2011
• 年：2011
• 卷：50
• 期：38
• 页码：8103-8106
• 全文大小：263K
• 年卷期：v.50,no.38(September 27, 2011)
• ISSN：1520-4995

文摘

Isocitrate dehydrogenase kinase/phosphatase (AceK) regulates entry into the glyoxylate bypass by reversibly phosphorylating isocitrate dehydrogenase (ICDH). On the basis of the recently determined structure of the AceK鈥揑CDH complex from Escherichia coli, we have classified the structures of homodimeric NADP⁺-ICDHs to rationalize and predict which organisms likely contain substrates for AceK. One example is Burkholderia pseudomallei (Bp). Here we report a crystal structure of Bp-ICDH that exhibits the necessary structural elements required for AceK recognition. Kinetic analyses provided further confirmation that Bp-ICDH is a substrate for AceK. We conclude that the highly stringent AceK binding sites on ICDH are maintained only in Gram-negative bacteria.