1ZA5

Q69H-FeSOD


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.199 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The Crucial Importance of Chemistry in the Structure-Function Link: Manipulating Hydrogen Bonding in Iron-Containing Superoxide Dismutase.

Yikilmaz, E.Rodgers, D.W.Miller, A.F.

(2006) Biochemistry 45: 1151-1161

  • DOI: 10.1021/bi051495d
  • Primary Citation of Related Structures:  
    2BKB, 1ZA5

  • PubMed Abstract: 
  • Fe-containing superoxide dismutase's active site Fe is coordinated by a solvent molecule, whose protonation state is coupled to the Fe oxidation state. Thus, we have proposed that H-bonding between glutamine 69 and this solvent molecule can strongly infl ...

    Fe-containing superoxide dismutase's active site Fe is coordinated by a solvent molecule, whose protonation state is coupled to the Fe oxidation state. Thus, we have proposed that H-bonding between glutamine 69 and this solvent molecule can strongly influence the redox activity of the Fe in superoxide dismutase (SOD). We show here that mutation of this Gln to His subtly alters the active site structure but preserves 30% activity. In contrast, mutation to Glu otherwise preserves the active site structure but inactivates the enzyme. Thus, enzyme function correlates not with atom positions but with residue identity (chemistry), in this case. We observe strong destabilization of the Q69E-FeSOD oxidized state relative to the reduced state and intermediate destabilization of oxidized Q69H-FeSOD. Indeed, redox titrations indicate that mutation of Gln69 to His increases the reduction potential by 240 mV, whereas mutation to Glu appears to increase it by more than 660 mV. We find that this suffices to explain the mutants' loss of activity, although additional factors may also contribute. The strongly elevated reduction potential of Q69E-FeSOD may reflect reorganization of the active site H-bonding network, including possible reversal of the polarity of the key H-bond between residue 69 and coordinated solvent.


    Organizational Affiliation

    Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Superoxide dismutase [Fe] AB192Escherichia coliMutation(s): 1 
Gene Names: sodB
EC: 1.15.1.1
Find proteins for P0AGD3 (Escherichia coli (strain K12))
Explore P0AGD3 
Go to UniProtKB:  P0AGD3
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.199 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.202α = 90
b = 84.921β = 108.37
c = 61.634γ = 90
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-03-14
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance