2I6Y

Structure and Mechanism of Mycobacterium tuberculosis Salicylate Synthase, MbtI


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.252 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Structure and mechanism of MbtI, the salicylate synthase from Mycobacterium tuberculosis

Zwahlen, J.Kolappan, S.Zhou, R.Kisker, C.Tonge, P.J.

(2007) Biochemistry 46: 954-964

  • DOI: 10.1021/bi060852x
  • Structures With Same Primary Citation

  • 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 ...

    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.


    Organizational Affiliation

    Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, USA.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Anthranilate synthase component I, putativeA470Mycobacterium tuberculosisMutation(s): 0 
Gene Names: mbtIMT2454Rv2386c
EC: 4.1.3.27 (PDB Primary Data), 5.4.99.5 (UniProt), 4.2.99.21 (UniProt), 5.4.4.2 (UniProt)
Find proteins for P9WFX1 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WFX1 
Go to UniProtKB:  P9WFX1
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.294 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.252 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.206α = 90
b = 143.603β = 90
c = 123.759γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
SOLVEphasing
RESOLVEphasing
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-06-19
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description