1q51
Crystal Structure of Mycobacterium tuberculosis MenB in Complex with Acetoacetyl-Coenzyme A, a Key Enzyme in Vitamin K2 Biosynthesis
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OverviewOverview
Bacterial enzymes of the menaquinone (Vitamin K2) pathway are potential, drug targets because they lack human homologs. MenB, 1,4-dihydroxy-2-naphthoyl-CoA synthase, the fourth enzyme in the, biosynthetic pathway leading from chorismate to menaquinone, catalyzes the, conversion of O-succinylbenzoyl-CoA (OSB-CoA) to, 1,4-dihydroxy-2-naphthoyl-CoA (DHNA-CoA). Based on our interest in, developing novel tuberculosis chemotherapeutics, we have solved the, structures of MenB from Mycobacterium tuberculosis and its complex with, acetoacetyl-coenzyme A at 1.8 and 2.3 A resolution, respectively. Like, other members of the crotonase superfamily, MenB folds as an (alpha3)2, hexamer, but its fold is distinct in that the C terminus crosses the, trimer-trimer interface, forming a flexible part of the active site within, the opposing trimer. The highly conserved active site of MenB contains a, deep pocket lined by Asp-192, Tyr-287, and hydrophobic residues., Mutagenesis shows that Asp-192 and Tyr-287 are essential for enzymatic, catalysis. We postulate a catalytic mechanism in which MenB enables proton, transfer within the substrate to yield an oxyanion as the initial step in, catalysis. Knowledge of the active site geometry and characterization of, the catalytic mechanism of MenB will aid in identifying new inhibitors for, this potential drug target.
About this StructureAbout this Structure
1Q51 is a Single protein structure of sequence from Mycobacterium tuberculosis h37rv with CAA as ligand. Active as Naphthoate synthase, with EC number 4.1.3.36 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of Mycobacterium tuberculosis MenB, a key enzyme in vitamin K2 biosynthesis., Truglio JJ, Theis K, Feng Y, Gajda R, Machutta C, Tonge PJ, Kisker C, J Biol Chem. 2003 Oct 24;278(43):42352-60. Epub 2003 Aug 8. PMID:12909628
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