1N0J: The Structure of Human Mitochondrial Mn3+ Superoxide Dismutase Reveals a Novel Tetrameric Interface of Two 4-helix Bundles

Citation:
Abstract
The 2.2 A resolution crystal structure of recombinant human manganese superoxide dismutase, a homotetrameric enzyme that protects mitochondria against oxygen-mediated free radical damage, has been determined. Within each subunit, both the N-terminal helical hairpin and C-terminal alpha/beta domains contribute ligands to the catalytic manganese site. Two identical 4-helix bundles, symmetrically assembled from the N-terminal helical hairpins, form novel tetrameric interfaces that stabilize the active sites. Structurally altered polymorphic variants with reduced activity, such as tetrameric interface mutant Ile-58 to Thr, may produce not only an early selective advantage, through enhanced cytotoxicity of tumor necrosis factor for virus-infected cells, but also detrimental effects from increased mitochondrial oxidative damage, contributing to degenerative conditions, including diabetes, aging, and Parkinson's and Alzheimer's diseases.
PDB ID: 1N0JDownload
MMDB ID: 21040
PDB Deposition Date: 2002/10/14
Updated in MMDB: 2007/11 
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Similar Structures:
Biological Unit for 1N0J: tetrameric; determined by author and by software (PISA,PQS)
Molecular Components in 1N0J
Label Count Molecule
Proteins (4 molecules)
4
Superoxide Dismutase [mn]
Molecule annotation
Chemicals (4 molecules)
1
4
* Click molecule labels to explore molecular sequence information.

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