5l02

S324T variant of B. pseudomallei KatG

spinqualitylabelsall models 5l02, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5l02 is a 2 chain structure with sequence from Burkholderia pseudomallei 1710b. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: HEM, MPD, NA, PO4, TOX Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function KATG_BURP1 Bifunctional enzyme with both catalase and broad-spectrum peroxidase activity. Publication Abstract from PubMed The Ser315Thr variant of the catalase-peroxidase KatG from Mycobacterium tuberculosis imparts resistance to the pro-drug isonicotinic acid hydrazide (isoniazid) through a failure to convert it to the active drug, isonicotinoyl-NAD. The equivalent variant in KatG from Burkholderia pseudomallei, Ser324Thr, has been constructed, revealing catalase and peroxidase activities that are similar to those of the native enzyme. The other activities of the variant protein, including the NADH oxidase, the isoniazid hydrazinolysis and isonicotinoyl-NAD synthase activities are reduced by 60-70%. The crystal structure of the variant differs from that of the native enzyme in having the methyl group of Thr324 situated in the entrance channel to the heme cavity, in a modified water matrix in the entrance channel and heme cavity, in lacking the putative perhydroxy modification on the heme, in the multiple locations of a few side-chains, and in the presence of an apparent perhydroxy modification on the indole nitrogen atom of the active-site Trp111. The position of the methyl group of Thr324 creates a constriction or narrowing of the channel leading to the heme cavity, providing an explanation for the lower reactivity towards isoniazid and the slower rate of isonicotinoyl-NAD synthesis. Structural characterization of the Ser324Thr variant of the catalase-peroxidase (KatG) from Burkholderia pseudomallei.,Deemagarn T, Carpena X, Singh R, Wiseman B, Fita I, Loewen PC J Mol Biol. 2005 Jan 7;345(1):21-8. PMID:15567407 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Catalase 3D structures

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