2wwi
Plasmodium falciparum thymidylate kinase in complex with AZTMP and ADP
Structural highlights
FunctionKTHY_PLAF7 Catalyzes the phosphorylation of thymidine monophosphate (dTMP) to thymidine diphosphate (dTDP), the immediate precursor for the DNA building block dTTP (PubMed:18477629, PubMed:19126267, PubMed:31934749, PubMed:20353400). Can also phosphorylate dGMP and to a lesser extent GMP, dUMP and dIMP (PubMed:18477629, PubMed:19126267, PubMed:31934749, PubMed:20353400). Can use either ATP or dATP as phosphate donors in presence of Mg(2+) (PubMed:18477629).[1] [2] [3] [4] 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 PubMedPlasmodium falciparum is the causative agent of malaria, a disease where new drug targets are required due to increasing resistance to current anti-malarials. TMPK (thymidylate kinase) is a good candidate as it is essential for the synthesis of dTTP, a critical precursor of DNA and has been much studied due to its role in prodrug activation and as a drug target. Type I TMPKs, such as the human enzyme, phosphorylate the substrate AZT (3'-azido-3'-deoxythymidine)-MP (monophosphate) inefficiently compared with type II TMPKs (e.g. Escherichia coli TMPK). In the present paper we report that eukaryotic PfTMPK (P. falciparum TMPK) presents sequence features of a type I enzyme yet the kinetic parameters for AZT-MP phosphorylation are similar to those of the highly efficient E. coli enzyme. Structural information shows that this is explained by a different juxtaposition of the P-loop and the azide of AZT-MP. Subsequent formation of the transition state requires no further movement of the PfTMPK P-loop, with no steric conflicts for the azide moiety, allowing efficient phosphate transfer. Likewise, we present results that confirm the ability of the enzyme to uniquely accept dGMP as a substrate and shed light on the basis for its wider substrate specificity. Information resulting from two ternary complexes (dTMP-ADP and AZT-MP-ADP) and a binary complex with the transition state analogue AP5dT [P1-(5'-adenosyl)-P5-(5'-thymidyl) pentaphosphate] all reveal significant differences with the human enzyme, notably in the lid region and in the P-loop which may be exploited in the rational design of Plasmodium-specific TMPK inhibitors with therapeutic potential. Structural basis for the efficient phosphorylation of AZT-MP (3'-azido-3'-deoxythymidine monophosphate) and dGMP by Plasmodium falciparum type I thymidylate kinase.,Whittingham JL, Carrero-Lerida J, Brannigan JA, Ruiz-Perez LM, Silva AP, Fogg MJ, Wilkinson AJ, Gilbert IH, Wilson KS, Gonzalez-Pacanowska D Biochem J. 2010 May 27;428(3):499-509. PMID:20353400[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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