Substrate recognition of isocitrate dehydrogenase and 3-isopropylmalate dehydrogenase from Thermus thermophilus HB8.
The substrate-binding sites of NADP-dependent isocitrate dehydrogenase and NAD-dependent 3-isopropylmalate dehydrogenase from Thermus thermophilus were analyzed by site-directed mutagenesis. Ser97 and Asn99 of isocitrate dehydrogenase were identified to be involved in the isocitrate recognition. In 3-isopropylmalate dehydrogenase, the corresponding residues, Leu90 and Leu91, appear to recognize the substrate by forming a hydrophobic pocket. Double mutation of Asp78 and Glu87 revealed that negative charge of these residues plays a crucial role in discriminating isopropylmalate from isocitrate.
Yaoi
T
T
Department of Life Science, Tokyo Institute of Technology, Yokohama.
Miyazaki
K
K
Oshima
T
T
D050539:3-Isopropylmalate Dehydrogenase; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001216:Asparagine / Q000235:genetics / Q000378:metabolism; D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D018698:Glutamic Acid / Q000235:genetics / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D012694:Serine / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D016963:Thermus thermophilus / Q000201:enzymology*
D001224:Aspartic Acid; D018698:Glutamic Acid; D012694:Serine; D001216:Asparagine; D000429:Alcohol Oxidoreductases; D007521:Isocitrate Dehydrogenase; D050539:3-Isopropylmalate Dehydrogenase