3G4Z

Crystal Structure of NiSOD Y9F mutant at 1.9 A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.87 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.186 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Role of conserved tyrosine residues in NiSOD catalysis: a case of convergent evolution

Herbst, R.W.Guce, A.Bryngelson, P.A.Higgins, K.A.Ryan, K.C.Cabelli, D.E.Garman, S.C.Maroney, M.J.

(2009) Biochemistry 48: 3354-3369

  • DOI: 10.1021/bi802029t
  • Primary Citation of Related Structures:  
    3G4X, 3G4Z, 3G50

  • PubMed Abstract: 
  • Superoxide dismutases rely on protein structural elements to adjust the redox potential of the metallocenter to an optimum value near 300 mV (vs NHE), to provide a source of protons for catalysis, and to control the access of anions to the active site. These aspects of the catalytic mechanism are examined herein for recombinant preparations of the nickel-dependent SOD (NiSOD) from Streptomyces coelicolor and for a series of mutants that affect a key tyrosine residue, Tyr9 (Y9F-, Y62F-, Y9F/Y62F-, and D3A-NiSOD) ...

    Superoxide dismutases rely on protein structural elements to adjust the redox potential of the metallocenter to an optimum value near 300 mV (vs NHE), to provide a source of protons for catalysis, and to control the access of anions to the active site. These aspects of the catalytic mechanism are examined herein for recombinant preparations of the nickel-dependent SOD (NiSOD) from Streptomyces coelicolor and for a series of mutants that affect a key tyrosine residue, Tyr9 (Y9F-, Y62F-, Y9F/Y62F-, and D3A-NiSOD). Structural aspects of the nickel sites are examined by a combination of EPR and X-ray absorption spectroscopies, and by single-crystal X-ray diffraction at approximately 1.9 A resolution in the case of Y9F- and D3A-NiSODs. The functional effects of the mutations are examined by kinetic studies employing pulse radiolytic generation of O2- and by redox titrations. These studies reveal that although the structure of the nickel center in NiSOD is unique, the ligand environment is designed to optimize the redox potential at 290 mV and results in the oxidation of 50% of the nickel centers in the oxidized hexamer. Kinetic investigations show that all of the mutant proteins have considerable activity. In the case of Y9F-NiSOD, the enzyme exhibits saturation behavior that is not observed in wild-type (WT) NiSOD and suggests that release of peroxide is inhibited. The crystal structure of Y9F-NiSOD reveals an anion binding site that is occupied by either Cl- or Br- and is located close to but not within bonding distance of the nickel center. The structure of D3A-NiSOD reveals that in addition to affecting the interaction between subunits, this mutation repositions Tyr9 and leads to altered chemistry with peroxide. Comparisons with Mn(SOD) and Fe(SOD) reveal that although different strategies for adjusting the redox potential and supply of protons are employed, NiSOD has evolved a similar strategy for controlling the access of anions to the active site.


    Organizational Affiliation

    Department of Chemistry, UniVersity of Massachusetts, Amherst, Massachusetts 01003, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Superoxide dismutase [Ni]A, B, C117Streptomyces coelicolorMutation(s): 1 
Gene Names: 2SC7G11.16cSCO5254sod1sodN
EC: 1.15.1.1
UniProt
Find proteins for P80735 (Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145))
Explore P80735 
Go to UniProtKB:  P80735
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.87 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.186 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.876α = 90
b = 111.577β = 90
c = 111.553γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
MOLREPphasing
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-04-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description
  • Version 1.3: 2017-11-29
    Changes: Database references