Crystal structures of mutants of Thermus thermophilus IPMDH adapted to low temperatures.
Random mutagenesis on thermophilic 3-isopropylmalate dehydrogenases (IPMDH; EC 1.1.1.85) produced mutant enzymes which adapt to low temperatures. These mutants had higher activity at lower temperatures than the wild-type enzyme without losing high thermostability. Here we report three structures of the mutants of Thermus thermophilus IPMDH determined by X-ray diffraction which was adapted to a low-temperature environment. Two of them have unstable coenzyme binding states and the other one probably has a stable substrate binding state. The present research suggests that the adaptation is correlated with the binding of either coenzyme or the substrate.
Hirose
R
R
Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuta 4259, Midori-ku, Yokohama 226-8501, Japan.
Suzuki
T
T
Moriyama
H
H
Sato
T
T
Yamagishi
A
A
Oshima
T
T
Tanaka
N
N
D050539:3-Isopropylmalate Dehydrogenase; D000222:Adaptation, Physiological / Q000235:genetics*; D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D003198:Computer Simulation; D003460:Crystallization; D018360:Crystallography, X-Ray; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D008293:Malates / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D008961:Models, Structural; D016296:Mutagenesis; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D013816:Thermodynamics; D016963:Thermus thermophilus / Q000201:enzymology* / Q000235:genetics
D007527:Isoenzymes; D008293:Malates; D011994:Recombinant Proteins; D000429:Alcohol Oxidoreductases; D050539:3-Isopropylmalate Dehydrogenase