1w2h
From Proteopedia
Crystal Structure Of Mycobacterium Tuberculosis Thymidylate Kinase Complexed With Azidothymidine Monophosphate (AZT-MP) (2.0 A Resolution)
Structural highlights
FunctionKTHY_MYCTU Catalyzes the reversible phosphorylation of deoxythymidine monophosphate (dTMP) to deoxythymidine diphosphate (dTDP), using ATP as its preferred phosphoryl donor. Situated at the junction of both de novo and salvage pathways of deoxythymidine triphosphate (dTTP) synthesis, is essential for DNA synthesis and cellular growth. Has a broad specificity for nucleoside triphosphates, being highly active with ATP or dATP as phosphate donors, and less active with ITP, GTP, CTP and UTP.[HAMAP-Rule:MF_00165] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTuberculosis (TB) is the primary cause of mortality among infectious diseases. Mycobacterium tuberculosis thymidylate kinase (TMPK(Mtub)) catalyzes the ATP-dependent phosphorylation of deoxythymidine 5'-monophosphate (dTMP). Essential to DNA replication, this enzyme represents a promising target for developing new drugs against TB, because the configuration of its active site is unique within the TMPK family. Indeed, it has been proposed that, as opposed to other TMPKs, catalysis by TMPK(Mtub) necessitates 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 is a substrate for human and other TMPKs. Here, the crystal structures of TMPK(Mtub) in complex with deoxythymidine (dT) and AZTMP were determined to 2.1 and 2.0 A resolution, respectively, and suggest a mechanism for inhibition. The azido group of AZTMP perturbs the induced-fit mechanism normally adopted by the enzyme. Magnesium is prevented from binding, and the resulting electrostatic environment precludes phosphoryl transfer from occurring. Our data provide a model for drug development against tuberculosis. The crystal structure of Mycobacterium tuberculosis thymidylate kinase in complex with 3'-azidodeoxythymidine monophosphate suggests a mechanism for competitive inhibition.,Fioravanti E, Adam V, Munier-Lehmann H, Bourgeois D Biochemistry. 2005 Jan 11;44(1):130-7. PMID:15628853[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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