Formation of the C ring in the lanosterol biosynthesis from squalene.
[reaction: see text] Ab initio calculations were performed on a cyclohexane derivative to elucidate the mechanism of the formation of the five-membered C ring in the biosynthesis of lanosterol from squalene. A conformational analysis of the side chain containing the double bond indicated that the conformer that should give rise to the cyclized C ring is not a minimum on the potential surface. Consequently, it is suggested that it is very likely that C-ring formation occurs in concert with formation of the A and B rings.
Hess
B Andes
BA
Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA. bahessjr@aol.com
D003500:Cyclization; D007810:Lanosterol / Q000096:biosynthesis*; D008958:Models, Molecular; D008968:Molecular Conformation; D013185:Squalene / Q000737:chemistry
D007810:Lanosterol; D013185:Squalene