C. Dahl, J. Dahl, K. Bloch
Jan 15, 1980
Citations
0
Influential Citations
33
Citations
Quality indicators
Journal
Biochemical and biophysical research communications
Abstract
Abstract Cycloartenol, a 9,19-cyclopropane sterol which is isomeric with lanosterol, showed an ability intermediate between lanosterol and cholesterol to increase the microviscosity of lecithin vesicles, to serve as a growth factor for the sterol auxotroph Mycoplasma capricolum , and to increase the microviscosity of M. capricolum membranes. The corresponding membrane effects of cyclolaudenol which contains a methyl group added to C-24 of the isooctenyl side chain of cycloartenol are more like those shown by lanosterol. We propose that the enhanced effectiveness of cycloartenol over lanosterol is due to a more favorable spatial disposition of the angular 14α-methyl group on the α-face of the molecule promoting more effective van der Waals contacts between the phospholipid fatty acyl chains and the sterol α-face. Side chain alkylation appears to perturb such contacts, reducing the effectiveness of cyclolaudenol for competent membrane function in M. capricolum .