2BMX

Mycobacterium tuberculosis AhpC

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.197 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history. 


Literature

Structure and Mechanism of the Alkyl Hydroperoxidase Ahpc, a Key Element of the Mycobacterium Tuberculosis Defense System Against Oxidative Stress.

Guimaraes, B.G., Souchon, H., Honore, N., Saint-Joanis, B., Brosch, R., Shepard, W., Cole, S.T., Alzari, P.M.

(2005) J Biol Chem 280: 25735

  • DOI: 10.1074/jbc.M503076200
  • Primary Citation of Related Structures:  
    2BMX

  • PubMed Abstract: 

    • The peroxiredoxin AhpC from Mycobacterium tuberculosis (MtAhpC) is the foremost element of a NADH-dependent peroxidase and peroxynitrite reductase system, where it directly reduces peroxides and peroxynitrite and is in turn reduced by AhpD and other proteins ...

    The peroxiredoxin AhpC from Mycobacterium tuberculosis (MtAhpC) is the foremost element of a NADH-dependent peroxidase and peroxynitrite reductase system, where it directly reduces peroxides and peroxynitrite and is in turn reduced by AhpD and other proteins. Overexpression of MtAhpC in isoniazid-resistant strains of M. tuberculosis harboring mutations in the catalase/peroxidase katG gene provides antioxidant protection and may substitute for the lost enzyme activities. We report here the crystal structure of oxidized MtAhpC trapped in an intermediate oligomeric state of its catalytic cycle. The overall structure folds into a ring-shaped hexamer of dimers instead of the usual pentamer of dimers observed in other reduced peroxiredoxins. Although the general structure of the functional dimer is similar to that of other 2-Cys peroxiredoxins, the alpha-helix containing the peroxidatic cysteine Cys61 undergoes a unique rigid-body movement to allow the formation of the disulfide bridge with the resolving cysteine Cys174. This conformational rearrangement creates a large internal cavity enclosing the active site, which might be exploited for the design of inhibitors that could block the catalytic cycle. Structural and mutagenesis evidence points to a model for the electron transfer pathway in MtAhpC that accounts for the unusual involvement of three cysteine residues in catalysis and suggests a mechanism by which MtAhpC can specifically interact with different redox partners.

    Organizational Affiliation: 

    Unité de Biochimie Structurale, CNRS URA 2185, 25 rue du Docteur Roux and Unité de Génétique Moléculaire Bactérienne, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ALKYL HYDROPEROXIDASE CA, B, C195Mycobacterium tuberculosis H37RvMutation(s): 1 
Gene Names: ahpC, Rv2428
EC: 1.11.1.15 (PDB Primary Data), 1.11.1.28 (UniProt)
UniProt
Find proteins for P9WQB7 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WQB7 
Go to UniProtKB:  P9WQB7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WQB7
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE		A, B, C L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.197 
  • Space Group: P 6 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 139.265α = 90
b = 139.265β = 90
c = 148.525γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
SHARPphasing

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-05-10
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance