Functional expression of cDNAs for bovine 11 beta-hydroxylase-aldosterone synthases, P450(11 beta)-2 and -3 and their chimeras.
Two molecular species of bovine P450(11 beta), P450(11 beta)-2 and P450(11 beta)-3 have been identified, in which the amino acid differences were found at the 6th, 36th and 82nd positions from the NH2-termini of the mature proteins. They catalyzed the 11 beta-, 18- and 19-hydroxylation and aldosterone formation from 11-deoxycorticosterone, and the rate of production of 18-hydroxycorticosterone and aldosterone by P450(11 beta)-3 was greater than that by P450(11 beta)-2 [Morohashi et al., J. Biochem. 107 (1990) 635-640]. In this study, chimeric clones were constructed whose 6th, 36th and 82nd amino acid residues were exchanged with each other. Two original clones and six chimeric clones were expressed in COS-7 cells, and their steroidogenic activities studied. The ratio of aldosterone or 18-hydroxycorticosterone production to corticosterone production by one clone was compared with that of the other. The ratios for the four clones having Gly36 [P450(11 beta)-3 type] were 0.08-0.22, whereas those for the clones having Ser36 [P450(11 beta)-2 type] were 0.03-0.05, suggesting that the Gly36 structure is important for aldosterone production.
Nonaka
Y
Y
Department of Biochemistry, Osaka University Medical School, Japan.
Okamoto
M
M
Morohashi
K
K
Kirita
S
S
Hashimoto
T
T
Omura
T
T
D000818:Animals; D002417:Cattle; D002460:Cell Line; D002678:Chimera; D019405:Cytochrome P-450 CYP11B2; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D015870:Gene Expression; D007700:Kinetics; D010957:Plasmids; D013252:Steroid 11-beta-Hydroxylase / Q000235:genetics* / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D019405:Cytochrome P-450 CYP11B2; D013252:Steroid 11-beta-Hydroxylase