| Co-Investigator(Kenkyū-buntansha) |
POULOU Thoma カリフォルニア大学, アーバイン校, 教授
HIROYA Kou Institute for Chemical Reaction Science, Tohoku University, 反応化学研究所, 助手 (70192721)
SHIMIZU Toru Institute for Chemical Reaction Science, Tohoku University, 反応化学研究所, 助教授 (40118956)
FUJII-KURIYAMA Yoshiaki Department of Chemistry, Faculty of Science, Tohoku University, 理学部, 教授 (00098146)
POULOS Thomas L. Department of Molecular Biology and Biochemistry, University of California, Irvi
POULOS Thoma メリーランド大学, 生化学科, 教授
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| Budget Amount *help |
¥5,500,000 (Direct Cost: ¥5,500,000)
Fiscal Year 1991: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1990: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
The cytochrome P450(P450) is one of the superfamily of heme-containing monooxygenases which catalyze many types of biotransformation reactions of organic substrates in living organisms. Significant progress in understanding the P450 structure-function relationship has been made on the basis of the X-ray crystal structure of water-soluble P450_<cam> and alignments of amino acids of P450s. By combining this knowledge and site-directed mutagenesis technique, the structure of membrane-bound P450_d(CYP1A2) was elucidated with respect to the heme incorporation (Biochemistry, 27, b4138-4141(1988)) and the structure of putative distal site (Biochemistry, 28, 6848-6857 (1989) ; Biochemistry, 30, 1490-1496(1991) ; Biochbmistry, 30, 4659-4662 (1991)). In this project we found the important role of Glu318 at the putative distal site' of P450_d(CYP1A2) in the packing or the conformational stability of the putative distal site of the P450_d molecule (Biochemistry, 30, 11206-11211(1991)) and the important role of the Glu318 in the catalytic function of the P450_d (Biochbmistry, 31, 1528-1531(1992)). Furthermore, we found that Lys94, Lys99, LYS105, Lys440, Lys453, Arg455, Lys463, and the Arg cluster, Arg135-Arg136-Arg137, of P450_d(CYP1A2) participate in the inter-molecular electron transfer process by forming ionic bridges between the P450_d and NADPH-P450 reductase and/or by orienting appropriate geometry for electron transfer on the interfacial surface between the two proteins (J. Biol. Chem., 266, 3372-3375(1991)). Well-conserved polar amino acids at position 318 of P450_d (Glu or Asp of P450s ; Asp251 of P450_<cam>) prior to the conserved Thr (Thr3l9 for P450_d ; Thr252 for P450_<cam>) significantly contribute to the activation of the oxygen molecule bound to P450.
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