The Crystal Structure of Mycobacterium tuberculosis Thymidylate Kinase in Complex with 3'-Azidodeoxythymidine Monophosphate Suggests a Mechanism for Competitive Inhibition

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• 作者：Emanuela Fioravanti ; Virgile Adam ; Hé ; lè ; ne Munier-Lehmann ; and Dominique Bourgeois
• 刊名：Biochemistry
• 出版年：2005
• 出版时间：January 11, 2005
• 年：2005
• 卷：44
• 期：1
• 页码：130 - 137
• 全文大小：552K
• 年卷期：v.44,no.1(January 11, 2005)
• ISSN：1520-4995

文摘

Tuberculosis (TB) is the primary cause of mortality among infectious diseases. Mycobacteriumtuberculosis thymidylate kinase (TMPK_Mtub) catalyzes the ATP-dependent phosphorylation of deoxythymidine 5'-monophosphate (dTMP). Essential to DNA replication, this enzyme represents a promisingtarget for developing new drugs against TB, because the configuration of its active site is unique withinthe TMPK family. Indeed, it has been proposed that, as opposed to other TMPKs, catalysis by TMPK_Mtubnecessitates the transient binding of a magnesium ion coordinating the phosphate acceptor. Moreover,3'-azidodeoxythymidine monophosphate (AZTMP) is a competitive inhibitor of TMPK_Mtub, whereas it isa substrate for human and other TMPKs. Here, the crystal structures of TMPK_Mtub in complex withdeoxythymidine (dT) and AZTMP were determined to 2.1 and 2.0 Å resolution, respectively, and suggesta mechanism for inhibition. The azido group of AZTMP perturbs the induced-fit mechanism normallyadopted by the enzyme. Magnesium is prevented from binding, and the resulting electrostatic environmentprecludes phosphoryl transfer from occurring. Our data provide a model for drug development againsttuberculosis.