Air-oxidized structure of the first GAF domain of Mycobacterium tuberculosis DosS

Experimental Data Snapshot

  • Resolution: 1.40 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.193 

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Structural Insight Into the Heme-Based Redox Sensing by Doss from Mycobacterium Tuberculosis.

Cho, H.Y.Cho, H.J.Kim, Y.M.Oh, J.I.Kang, B.S.

(2009) J Biol Chem 284: 13057

  • DOI: https://doi.org/10.1074/jbc.M808905200
  • Primary Citation of Related Structures:  
    2W3D, 2W3E, 2W3F, 2W3G, 2W3H

  • PubMed Abstract: 

    Mycobacterium tuberculosis is thought to undergo transformation into its non-replicating persistence state under the influence of hypoxia or nitric oxide (NO). This transformation is thought to be mediated via two sensor histidine kinases, DosS and DosT, each of which contains two GAF domains that are responsible for detecting oxygen tension. In this study we determined the crystal structures of the first GAF domain (GAF-A) of DosS, which shows an interaction with a heme. A b-type heme was embedded in a hydrophobic cavity of the GAF-A domain and was roughly perpendicular to the beta-sheet of the GAF domain. The heme iron was liganded by His-149 at the proximal heme axial position. The iron, in the oxidized form, was six-coordinated with a water molecule at the distal position. Upon reduction, the iron, in ferrous form, was five-coordinated, and when the GAF domain was exposed to atmospheric O(2), the ferrous form was oxidized to generate the Met form rather than a ferrous O(2)-bound form. Because the heme is isolated inside the GAF domain, its accessibility is restricted. However, a defined hydrogen bond network found at the heme site could accelerate the electron transferability and would explain why DosS was unable to bind O(2). Flavin nucleotides were shown to reduce the heme iron of DosS while NADH was unable to do so. These results suggest that DosS is a redox sensor and detects hypoxic conditions by its reduction.

  • Organizational Affiliation

    School of Life Science and Biotechnology, Kyungpook National University, Daegu, Korea.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
153Mycobacterium tuberculosisMutation(s): 0 
EC: 2.7.3
Find proteins for P9WGK3 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WGK3 
Go to UniProtKB:  P9WGK3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WGK3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.40 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.193 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 36.351α = 90
b = 86.801β = 90
c = 100.791γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-03-10
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance