2i6y

Structure and Mechanism of Mycobacterium tuberculosis Salicylate Synthase, MbtI

spinqualitylabelsall models 2i6y, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2i6y is a 1 chain structure with sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: mbtI, MT2454, Rv2386c (Mycobacterium tuberculosis) Activity: Anthranilate synthase, with EC number 4.1.3.27 Resources: FirstGlance, OCA, RCSB, PDBsum, TOPSAN 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 PubMed MbtI (rv2386c) from Mycobacterium tuberculosis catalyzes the initial transformation in mycobactin biosynthesis by converting chorismate to salicylate. We report here the structure of MbtI at 2.5 A resolution and demonstrate that isochorismate is a kinetically competent intermediate in the synthesis of salicylate from chorismate. At pH values below 7.5 isochorismate is the dominant product while above this pH value the enzyme converts chorismate to salicylate without the accumulation of isochorismate in solution. The salicylate and isochorismate synthase activities of MbtI are Mg2+-dependent, and in the absence of Mg2+ MbtI has a promiscuous chorismate mutase activity similar to that of the isochorismate pyruvate lyase, PchB, from Pseudomonas aeruginosa. MbtI is part of a larger family of chorismate-binding enzymes descended from a common ancestor (the MST family), that includes the isochorismate synthases and anthranilate synthases. The lack of active site residues unique to pyruvate eliminating members of this family, combined with the observed chorismate mutase activity, suggests that MbtI may exploit a sigmatropic pyruvate elimination mechanism similar to that proposed for PchB. Using a combination of structural, kinetic, and sequence based studies we propose a mechanism for MbtI applicable to all members of the MST enzyme family. Structure and mechanism of MbtI, the salicylate synthase from Mycobacterium tuberculosis.,Zwahlen J, Kolappan S, Zhou R, Kisker C, Tonge PJ Biochemistry. 2007 Jan 30;46(4):954-64. PMID:17240979 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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