2QKC

Structural and Kinetic Study of the Differences between Human and E.coli Manganese Superoxide Dismutases


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.199 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural and kinetic study of differences between human and Escherichia coli manganese superoxide dismutases.

Zheng, J.Domsic, J.F.Cabelli, D.McKenna, R.Silverman, D.N.

(2007) Biochemistry 46: 14830-14837

  • DOI: 10.1021/bi7014103
  • Primary Citation of Related Structures:  
    2QKC, 2QKA

  • PubMed Abstract: 
  • Human manganese superoxide dismutase (MnSOD) is characterized by a product inhibition stronger than that observed in bacterial forms of MnSOD. Previous studies show that the conserved, active-site residue Tyr34 mediates product inhibition; however, the protein environment of Tyr34 is different in human and Escherichia coli MnSOD ...

    Human manganese superoxide dismutase (MnSOD) is characterized by a product inhibition stronger than that observed in bacterial forms of MnSOD. Previous studies show that the conserved, active-site residue Tyr34 mediates product inhibition; however, the protein environment of Tyr34 is different in human and Escherichia coli MnSOD. We have prepared two site-specific mutants of human MnSOD with replacements of Phe66 with Ala and Leu (F66A and F66L, respectively), altering the surroundings of Tyr34. Pulse radiolysis was used to generate superoxide, and measurements of catalysis were taken in single-turnover experiments by observing the visible absorbance of species of MnSOD and under catalytic conditions observing the absorbance of superoxide. The mutation of Phe66 to Leu resulted in a mutant of human MnSOD with weakened product inhibition resembling that of E. coli MnSOD. Moreover, the mechanism of this weakened product inhibition was similar to that in E. coli MnSOD, specifically a decrease in the rate constant for the oxidative addition of superoxide to Mn2+MnSOD leading to the formation of the peroxide-inhibited enzyme. In addition, the crystal structures of both mutants have been determined and compared to those of wild-type human and E. coli MnSOD. The crystallographic data suggest that the solvent structure and its mobility as well as side chain conformations may affect the extent of product inhibition. These data emphasize the role of residue 66 in catalysis and inhibition and provide a structural explanation for differences in catalytic properties between human and certain bacterial forms of MnSOD.


    Organizational Affiliation

    Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Superoxide dismutase [Mn]A, B [auth C]196Homo sapiensMutation(s): 1 
Gene Names: SOD2
EC: 1.15.1.1
UniProt & NIH Common Fund Data Resources
Find proteins for P04179 (Homo sapiens)
Explore P04179 
Go to UniProtKB:  P04179
PHAROS:  P04179
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

Download Ideal Coordinates CCD File 
C [auth A], D [auth C]MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.199 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.108α = 90
b = 81.108β = 90
c = 242.545γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
PDB_EXTRACTdata extraction
CrystalCleardata collection
CNSphasing

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-07-29
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-18
    Changes: Refinement description