Use of Cyclodextrins to Monitor Transbilayer Movement and Differential Lipid Affinities of Cholesterol

摘要: In view of the demonstrated cholesterol-binding capabilities certain cyclodextrins, we have examined whether these agents can also catalyze efficient transfer cholesterol between lipid vesicles. We here demonstrate that beta- and gamma-cyclodextrins dramatically accelerate rate vesicles under conditions where a negligible fraction sterol is bound to cyclodextrin in steady state. gamma-cyclodextrin enhance by larger factor than they phospholipid, whereas, for alpha- methyl-beta-cyclodextrin, opposite true. Analysis kinetics cyclodextrin-mediated large unilamellar composed mainly 1-stearoyl-2-oleoyl phosphatidylcholine (SOPC) or SOPC/cholesterol indicates transbilayer flip-flop very rapid (halftime < 1-2 min at 37 degrees C). Using beta-cyclodextrin transfer, measured relative affinities variety different species. Our results show strong variations affinity phospholipids bearing chain unsaturation lesser, albeit significant, effects phospholipid headgroup structure on affinity. findings confirm previous suggestions interacts with markedly higher sphingolipids common membrane phospholipids.