1GN3

H145Q mutant of Mycobacterium tuberculosis iron-superoxide dismutase.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 4 Å
  • R-Value Free: 0.184 
  • R-Value Work: 0.168 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Engineering a Change in the Metal-Ion Specificity of the Iron-Depedent Superoxide Dismutase from Mycobacterium Tuberculosis. X-Ray Structure Analysis of Site-Directed Mutants.

Bunting, K.A.Cooper, J.B.Badasso, M.O.Tickle, I.J.Newton, M.Wood, S.P.Young, D.B.

(1998) Eur.J.Biochem. 251: 795

  • Primary Citation of Related Structures:  1GN4
  • Also Cited By: 1GN2

  • PubMed Abstract: 
  • We have refined the X-ray structures of two site-directed mutants of the iron-dependent superoxide dismutase (SOD) from Mycobacterium tuberculosis. These mutations which affect residue 145 in the enzyme (H145Q and H145E) were designed to alter its me ...

    We have refined the X-ray structures of two site-directed mutants of the iron-dependent superoxide dismutase (SOD) from Mycobacterium tuberculosis. These mutations which affect residue 145 in the enzyme (H145Q and H145E) were designed to alter its metal-ion specificity. This residue is either Gln or His in homologous SOD enzymes and has previously been shown to play a role in active-site interactions since its side-chain helps to coordinate the metal ion via a solvent molecule which is thought to be a hydroxide ion. The mutations were based on the observation that in the closely homologous manganese dependent SOD from Mycobacterium leprae, the only significant difference from the M. tuberculosis SOD within 10 A of the metal-binding site is the substitution of Gln for His at position 145. Hence an H145Q mutant of the M. tuberculosis (TB) SOD was engineered to investigate this residue's role in metal ion dependence and an isosteric H145E mutant was also expressed. The X-ray structures of the H145Q and H145E mutants have been solved at resolutions of 4.0 A and 2.5 A, respectively, confirming that neither mutation has any gross effects on the conformation of the enzyme or the structure of the active site. The residue substitutions are accommodated in the enzyme's three-dimensional structure by small local conformational changes. Peroxide inhibition experiments and atomic absorption spectroscopy establish surprisingly the H145E mutant SOD has manganese bound to it whereas the H145Q mutant SOD retains iron as the active-site metal. This alteration in metal specificity may reflect on the preference of manganese ions for anionic ligands.


    Organizational Affiliation

    Department of Crystallography, Birkbeck College, University of London, England.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SUPEROXIDE DISMUTASE
A, B
207Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)Gene Names: sodB (sod, sodA)
EC: 1.15.1.1
Find proteins for P9WGE7 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Go to UniProtKB:  P9WGE7
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FE
Query on FE

Download SDF File 
Download CCD File 
A, B
FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 4 Å
  • R-Value Free: 0.184 
  • R-Value Work: 0.168 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 103.880α = 90.00
b = 103.880β = 90.00
c = 69.920γ = 120.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
CCP4phasing
SCALAdata scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-10-05
    Type: Initial release
  • Version 1.1: 2011-06-02
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance