The influence of branched-chain and omega-alicyclic fatty acids on the transition temperature of bacillus subtilis lipids.

The influence of branched-chain and omega-alicyclic fatty acids on the transition temperature of Bacillus subtilis lipids was studied by measuring the fluorescence depolarisation of the probe 1,6-diphenyl-1,3,5-hexatriene incorporated into lipid bilayers. Only anteiso-C15 and C17 fatty acid-enriched lipids showed no transition in the observed temperature range. Compared to the transition of normal lipids iso-fatty acid-enriched lipids have a slightly higher transition temperature. The incorporation of omega-alicyclic fatty acids with increasing size of the alicycle leads to a decrease in the transition temperature. A possible role of omega-cyclohexane fatty acids in Bacillus acidocaldarius is proposed.