1VAR

MITOCHONDRIAL MANGANESE SUPEROXIDE DISMUTASE VARIANT WITH ILE 58 REPLACED BY THR


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Work: 0.170 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Human mitochondrial manganese superoxide dismutase polymorphic variant Ile58Thr reduces activity by destabilizing the tetrameric interface.

Borgstahl, G.E.Parge, H.E.Hickey, M.J.Johnson, M.J.Boissinot, M.Hallewell, R.A.Lepock, J.R.Cabelli, D.E.Tainer, J.A.

(1996) Biochemistry 35: 4287-4297

  • DOI: 10.1021/bi951892w

  • PubMed Abstract: 
  • Human manganese superoxide dismutase (MnSOD) is a homotetrameric enzyme which protects mitochondria against oxygen-mediated free radical damage. Within each subunit, both the N-terminal helical hairpin and C-terminal alpha/beta domains contribute lig ...

    Human manganese superoxide dismutase (MnSOD) is a homotetrameric enzyme which protects mitochondria against oxygen-mediated free radical damage. Within each subunit, both the N-terminal helical hairpin and C-terminal alpha/beta domains contribute ligands to the catalytic manganese site. Two identical four-helix bundles, symmetrically assembled from the N-terminal helical hairpins, form a novel tetrameric interface that stabilizes the active sites. The 2.5 A crystallographic structure of the naturally occurring polymorphic variant Ile58Thr MnSOD reveals that the helical hairpin mutation Thr58 causes two packing defects in each of the two four-helix bundles of the tetrameric interface. Similar mutations, expected to cause packing defects in the Cu,ZnSOD dimer interface, are associated with the degenerative disease amyotrophic lateral sclerosis. Ile58Thr MnSOD is primarily dimeric in solution and is significantly less thermostable than the normal enzyme, with decreases of 15 degrees C in the main melting temperature and 20 degrees C in the heat-inactivation temperature. Consequently, this mutant MnSOD is compromised at normal body temperatures: thermal inactivation, predicted from the decrease in thermal stability, occurs with a theoretical half-life of only 3.2 h at 37 degrees C (1.4 h at 41 degrees C), compared with 3.1 years for native MnSOD. This prediction is supported by direct measurements: incubation at 41.7 degrees C for 3 h has no effect on the activity of native MnSOD but completely inactivates mutant MnSOD. Rapid inactivation of Ile58Thr MnSOD at the elevated temperatures associated with fever and inflammation could provide an early advantage by killing infected cells, but also would increase superoxide-mediated oxidative damage and perhaps contribute to late-onset diseases.


    Related Citations: 
    • The Structure of Human Mitochondrial Manganese Superoxide Dismutase Reveals a Novel Tetrameric Interface of Two 4-Helix Bundles
      Borgstahl, G.E.,Parge, H.E.,Hickey, M.J.,Beyer Junior, W.F.,Hallewell, R.A.,Tainer, J.A.
      (1992) Cell 71: 107


    Organizational Affiliation

    Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MANGANESE SUPEROXIDE DISMUTASE
A, B
198Homo sapiensGene Names: SOD2
EC: 1.15.1.1
Find proteins for P04179 (Homo sapiens)
Go to Gene View: SOD2
Go to UniProtKB:  P04179
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN3
Query on MN3

Download SDF File 
Download CCD File 
A, B
MANGANESE (III) ION
Mn
MMIPFLVOWGHZQD-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Work: 0.170 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 75.000α = 90.00
b = 78.100β = 90.00
c = 68.100γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
X-PLORphasing
X-PLORmodel building
X-PLORrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1996-06-10
    Type: Initial release
  • Version 1.1: 2008-03-03
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-11-29
    Type: Derived calculations, Other