1COJ

FE-SOD FROM AQUIFEX PYROPHILUS, A HYPERTHERMOPHILIC BACTERIUM

Summary for 1COJ

• Entry DOI: 10.2210/pdb1coj/pdb
• Descriptor: PROTEIN (SUPEROXIDE DISMUTASE), FE (III) ION (3 entities in total)
• Functional Keywords: oxidoreductase
• Biological source: Aquifex pyrophilus
• Total number of polymer chains: 1
• Total formula weight: 24432.44

Authors

Lim, J.H.,Yu, Y.G.,Kim, S.-H.,Cho, S.-J.,Ahn, B.Y.,Han, Y.S.,Cho, Y. (deposition date: 1999-05-28, release date: 1999-06-14, Last modification date: 2023-12-27)

Primary citation

Lim, J.H.,Yu, Y.G.,Han, Y.S.,Cho, S.,Ahn, B.Y.,Kim, S.H.,Cho, Y.
The crystal structure of an Fe-superoxide dismutase from the hyperthermophile Aquifex pyrophilus at 1.9 A resolution: structural basis for thermostability.
J.Mol.Biol., 270:259-274, 1997

PubMed Abstract: Superoxide dismutase (SOD) from Aquifex pyrophilus, a hyperthermophilic bacterium, is an extremely heat-stable enzyme that maintains about 70% of its activity after heat treatment for 60 minutes at 100 degrees C. To understand the molecular basis of thermostability of this enzyme, we have determined the crystal structure of A. pyrophilus superoxide dismutase (Ap SOD), an Fe containing homotetrameric enzyme, at 1.9 A resolution, and compared it with SOD structures from a mesophile and a thermophile, and other enzyme structures from other hyperthermophiles. The structure has been refined to a crystallographic R-factor (I > 2sigma) of 17.0% and R-free (I > 2sigma) of 19.9%. While the overall structure of the Ap SOD monomer is similar to the other SODs, significant conformational differences are observed in a highly variable loop region and the C-terminal helix. The conformational differences in these regions alter the subunit arrangement of this enzyme and generate a very compact tetramer. Structural comparisons of three SODs have revealed that Ap SOD has some stabilizing features at both the tertiary and the quaternary structural level: The Ap SOD monomer contains a large number of ion-pairs and the Ap SOD tetramer has a dramatically increased buried surface area per monomer. Comparisons of the Ap SOD structure with that of other known enzymes from hyperthermophiles reveal that the increased number of intrasubunit ion-pairs is a common feature.

PubMed: 9236127
DOI: 10.1006/jmbi.1997.1105

Experimental method

X-RAY DIFFRACTION (1.9 Å)