Lim, JH Yu, YG Han, YS Cho, SJ Ahn, BY Kim, SH Cho, YJ 2024-01-21T18:11:11Z 2024-01-21T18:11:11Z 2022-01-11 1997-07-11 0022-2836 https://pubs.kist.re.kr/handle/201004/143703 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 Angstrom 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 X-factor (I > 2 sigma) of 17.0% and R-free (I > 2 sigma) 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. (C) 1997 Academic Press Limited. English ACADEMIC PRESS LTD MYCOBACTERIUM-TUBERCULOSIS 2.5-ANGSTROM RESOLUTION THERMUS-THERMOPHILUS PROTEIN-STRUCTURE MANGANESE IRON STABILITY ENZYMES PROGRAM DEHYDROGENASE The crystal structure of an Fe-superoxide dismutase from the hyperthermophile Aquifex pyrophilus at 1.9 angstrom resolution: Structural basis for thermostability Article 10.1006/jmbi.1997.1105 1 JOURNAL OF MOLECULAR BIOLOGY, v.270, no.2, pp.259 - 274 JOURNAL OF MOLECULAR BIOLOGY 270 2 259 274 scie scopus A1997XK87700012 2-s2.0-0030748521 Biochemistry & Molecular Biology Biochemistry & Molecular Biology Article MYCOBACTERIUM-TUBERCULOSIS 2.5-ANGSTROM RESOLUTION THERMUS-THERMOPHILUS PROTEIN-STRUCTURE MANGANESE IRON STABILITY ENZYMES PROGRAM DEHYDROGENASE superoxide dismutase hyperthermophile ion-pair thermostability Aquifex pyrophilus