[Algorithm of channel gating and its allosteric regulation by membrane cholesterol]

A method for quantitative analysis of channel kinetics was established with the use of histograms of channel events. In this system, channel kinetics was expressed as an exponential function of temperatures. The two factors in this exponential function were independently regulated: one was the progressive index number, controlled by membrane cholesterol, and the other was the coefficient, directed by channel gramicidin. Mean frequencies of channel opening decreased depending on cholesterol concentrations in the membrane. Its sigmoidal nature suggested that cholesterol regulated the channel characteristics in allosteric manner. The theoretical formula to analyze channel kinetics from the exponental as a function of temperatures, channel and membrane cholesterol concentrations was confirmed to be valid by comparison with experimental results.