The influence of n-alkanols and cholesterol on the duration and conductance of gramicidin single channels in monoolein bilayers.
The mean lifetime of gramicidin A channels in bilayers formed from monoolein and squalane was sharply reduced by the absorption of a range of n-alkanols and cholesterol. Results are shown for n-hexanol, n-octanol, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol and cholesterol. The longer chain n-alkanols were apparently more effective than the shorter members and cholesterol was the most effective of the substances examined. The single channel conductance was also affected, though to a much lesser extent than the mean channel lifetime, the n-alkanols producing increases and cholesterol a decrease. It is suggested that membrane fluidity changes are not likely to be primarily responsible for the reductions in channel lifetimes but that the bilayer tension, which is known to be increased by n-octanol, could be significant.
D000438:Alcohols; D002784:Cholesterol; D004553:Electric Conductivity; D005989:Glycerides; D006096:Gramicidin; D007473:Ion Channels; D008563:Membrane Lipids; D013997:Time Factors
D000438:Alcohols; D005989:Glycerides; D007473:Ion Channels; D008563:Membrane Lipids; D006096:Gramicidin; D002784:Cholesterol; C005953:monoolein