Loop Dynamics and Ligand Binding Kinetics in the Reaction Catalyzed by the Yersinia Protein Tyrosine Phosphatase

详细信息    查看全文

• 作者：Mazdak Khajehpour ; Li Wu ; Sijiu Liu ; Nick Zhadin ; Zhong-Yin Zhang ; Robert Callender
• 刊名：Biochemistry
• 出版年：2007
• 出版时间：April 10, 2007
• 年：2007
• 卷：46
• 期：14
• 页码：4370 - 4378
• 全文大小：216K
• 年卷期：v.46,no.14(April 10, 2007)
• ISSN：1520-4995

文摘

The Yersinia protein tyrosine phosphatase (YopH) contains a loop of ten amino acids (theWPD loop) that covers the entrance of the active site of the enzyme during substrate binding. In thiswork the substrate mimicking competitive inhibitor p-nitrocatechol sulfate (PNC) is used as a probe ofthe active site. The dynamics of the WPD loop was determined by subjecting an equilibrated systemcontaining YopH, PNC, and YopH bound to PNC to a laser induced temperature jump, and subsequentlyfollowing the change in equilibrium due to the perturbation. Using this methodology the dynamics associatedwith substrate binding in YopH have been determined. These results indicate that substrate binding iscoupled to the WPD loop motion, and WPD loop dynamics occur in the sub-millisecond time scale. Thesignificance of these dynamic results is interpreted in terms of the catalytic cycle of the enzyme.