1-methylidenesqualene and 25-methylidenesqualene as active-site probes for bacterial squalene:hopene cyclase.
1-methylidenesqualene and 25-methylidenesqualene were converted to 30-methylidenehop-22(29)-ene by squalene:hopene cyclase from Alicyclobacillus acidocaldarius. It was remarkable that both analogues generated the same product. The hopanyl intermediate cation, stabilized by the methylidene residue, enabled a rotation of the isobutenyl group at C-21 prior to the final proton elimination. In contrast, in the formation of hop-22(29)-ene, the final proton abstraction takes place regiospecifically from the Z-methyl group, which was verified by cyclization of (1,1,1,24,24,24-(2)H(6))squalene into (23,23,23,30,30,30-(2)H(6))hop-22(29)-ene. [reaction: see text]
Tanaka
Hideya
H
University of Shizuoka, School of Pharmaceutical Sciences, 2-1 Yada, Shizuoka 422-8526, Japan.
Noguchi
Hiroshi
H
Abe
Ikuro
I
D001407:Bacillus / Q000201:enzymology*; D001665:Binding Sites; D016937:Gram-Positive Endospore-Forming Rods / Q000201:enzymology*; D019751:Intramolecular Transferases / Q000032:analysis*; D015335:Molecular Probes; D015394:Molecular Structure; D013185:Squalene / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000378:metabolism
C487229:1-methylidenesqualene; C487230:25-methylidenesqualene; D015335:Molecular Probes; D013185:Squalene; D019751:Intramolecular Transferases; C066630:squalene-hopene cyclase