Abstract
Cell membranes are composed of various glycerophospholipids and sphingolipids. Cholesterol is believed to interact with these phospholipids to modulate the fluidity of the membrane. We have introduced a novel approach to measure the preferential interaction of cholesterol with different classes of phospholipids having different head-groups and acyl-chain compositions. Phospholipids involved in the study are phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylserine (PS) and sphingomyelin (SM). These phospholipid classes constitute the bulk of the membrane phospholipids. The acyl chain configurations of the saturated and unsaturated glycerophospholipids involved in this study are di 16:0 and 16:0(sn1)-18:1(sn2) respectively. Correspondingly, the N-linked acyl chain configurations in SMs are 16:0 and 18:1(Δ9-cis). Affinity of sterol analogs cholestatrienol and bodipy-cholesterol towards phospholipid bilayers is also studied to compare their affinities with cholesterol. Large unilamellar vesicle (LUV) systems with (sterol) donor vesicles and (sterol) acceptor vesicles are used. Acceptor LUVs are allowed to accept the sterol from donor vesicles, transfer being assisted by methyl-β-cyclodextrin. Diphenylhexatriene-phosphatidylcholine (DPHPC) was used as a fluorescent probe in cholesterol donor acceptor anisotropy experiments. We observed that cholesterol showed different affinity for phospholipids as compared to its fluorescent analogs. Affinity of cholesterol and the fluorescent analogs for different phospholipid bilayers depended not only on the head groups of the phospholipids but also on their acyl chain configuration.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call