2R27

Constitutively zinc-deficient mutant of human superoxide dismutase (SOD), C6A, H80S, H83S, C111S


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.184 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS.

Roberts, B.R.Tainer, J.A.Getzoff, E.D.Malencik, D.A.Anderson, S.R.Bomben, V.C.Meyers, K.R.Karplus, P.A.Beckman, J.S.

(2007) J.Mol.Biol. 373: 877-890

  • DOI: 10.1016/j.jmb.2007.07.043

  • PubMed Abstract: 
  • Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of patients with familial amyotrophic lateral sclerosis (ALS). Despite their widespread distribution, ALS mutations appe ...

    Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of patients with familial amyotrophic lateral sclerosis (ALS). Despite their widespread distribution, ALS mutations appear positioned to cause structural and misfolding defects. Such defects decrease SOD's affinity for zinc, and loss of zinc from SOD is sufficient to induce apoptosis in motor neurons in vitro. To examine the importance of the zinc site in the structure and pathogenesis of human SOD, we determined the 2.0-A-resolution crystal structure of a designed zinc-deficient human SOD, in which two zinc-binding ligands have been mutated to hydrogen-bonding serine residues. This structure revealed a 9 degrees twist of the subunits, which opens the SOD dimer interface and represents the largest intersubunit rotational shift observed for a human SOD variant. Furthermore, the electrostatic loop and zinc-binding subloop were partly disordered, the catalytically important Arg143 was rotated away from the active site, and the normally rigid intramolecular Cys57-Cys146 disulfide bridge assumed two conformations. Together, these changes allow small molecules greater access to the catalytic copper, consistent with the observed increased redox activity of zinc-deficient SOD. Moreover, the dimer interface is weakened and the Cys57-Cys146 disulfide is more labile, as demonstrated by the increased aggregation of zinc-deficient SOD in the presence of a thiol reductant. However, equimolar Cu,Zn SOD rapidly forms heterodimers with zinc-deficient SOD (t1/2 approximately 15 min) and prevents aggregation. The stabilization of zinc-deficient SOD as a heterodimer with Cu,Zn SOD may contribute to the dominant inheritance of ALS mutations. These results have general implications for the importance of framework stability on normal metalloenzyme function and specific implications for the role of zinc ion in the fatal neuropathology associated with SOD mutations.


    Organizational Affiliation

    Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Superoxide dismutase [Cu-Zn]
A, B
154Homo sapiensMutation(s): 4 
Gene Names: SOD1
EC: 1.15.1.1
Find proteins for P00441 (Homo sapiens)
Go to Gene View: SOD1
Go to UniProtKB:  P00441
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CU
Query on CU

Download SDF File 
Download CCD File 
A, B
COPPER (II) ION
Cu
JPVYNHNXODAKFH-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.184 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 107.200α = 90.00
b = 35.900β = 104.80
c = 68.300γ = 90.00
Software Package:
Software NamePurpose
MAR345dtbdata collection
CNSphasing
SCALEPACKdata scaling
CNSrefinement
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-12-11
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Atomic model, Version format compliance