2I6Y

Structure and Mechanism of Mycobacterium tuberculosis Salicylate Synthase, MbtI

2I6Y の概要

• エントリーDOI: 10.2210/pdb2i6y/pdb
• 分子名称: Anthranilate synthase component I, putative (2 entities in total)
• 機能のキーワード: beta sheet, lyase
• 由来する生物種: Mycobacterium tuberculosis
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 50950.52

構造登録者

Zwahlen, J.,Subramaniapillai, K.,Zhou, R.,Kisker, C.,Tonge, P.J. (登録日: 2006-08-29, 公開日: 2007-06-19, 最終更新日: 2024-02-21)

主引用文献

Zwahlen, J.,Kolappan, S.,Zhou, R.,Kisker, C.,Tonge, P.J.
Structure and mechanism of MbtI, the salicylate synthase from Mycobacterium tuberculosis
Biochemistry, 46:954-964, 2007

PubMed Abstract: 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.

PubMed: 17240979
DOI: 10.1021/bi060852x

実験手法

X-RAY DIFFRACTION (2.5 Å)