1mrn
CRYSTAL STRUCTURE OF MYCOBACTERIUM TUBERCULOSIS THYMIDYLATE KINASE COMPLEXED WITH BISUBSTRATE INHIBITOR (TP5A)
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OverviewOverview
The chemical synthesis of new compounds designed as inhibitors of, Mycobacterium tuberculosis TMP kinase (TMPK) is reported. The synthesis, concerns TMP analogues modified at the 5-position of the thymine ring as, well as a novel compound with a six-membered sugar ring. The binding, properties of the analogues are compared with the known inhibitor, azido-TMP, which is postulated here to work by excluding the TMP-bound, Mg(2+) ion. The crystallographic structure of the complex of one of the, compounds, 5-CH(2)OH-dUMP, with TMPK has been determined at 2.0 A. It, reveals a major conformation for the hydroxyl group in contact with a, water molecule and a minor conformation pointing toward Ser(99). Looking, for a role for Ser(99), we have identified an unusual catalytic triad, or, a proton wire, made of strictly conserved residues (including Glu(6), Ser(99), Arg(95), and Asp(9)) that probably serves to protonate the, transferred PO(3) group. The crystallographic structure of the, commercially available bisubstrate analogue, P(1)-(adenosine-5')-P(5)-(thymidine-5')-pentaphosphate bound to TMPK is, also reported at 2.45 A and reveals an alternative binding pocket for the, adenine moiety of the molecule compared with what is observed either in, the Escherichia coli or in the yeast enzyme structures. This alternative, binding pocket opens a way for the design of a new family of specific, inhibitors.
About this StructureAbout this Structure
1MRN is a Single protein structure of sequence from Mycobacterium tuberculosis with SO4, MG and T5A as ligands. Active as dTMP kinase, with EC number 2.7.4.9 Full crystallographic information is available from OCA.
ReferenceReference
Enzymatic and structural analysis of inhibitors designed against Mycobacterium tuberculosis thymidylate kinase. New insights into the phosphoryl transfer mechanism., Haouz A, Vanheusden V, Munier-Lehmann H, Froeyen M, Herdewijn P, Van Calenbergh S, Delarue M, J Biol Chem. 2003 Feb 14;278(7):4963-71. Epub 2002 Nov 25. PMID:12454011
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