CHANNEL MECHANISM FOR ELECTROGENIC ION PUMPS

A model of active ion transport is analyzed in which an essential part of the pump molecule is an ion channel. Ion translocation in the channel is described as a series of jumps between binding sites which are separated by energy barriers. Pumping action results from a transient energy-dependent modification of the barrier structure of the channel and requires only minor conformational changes of the pump molecule. This model is applied to the lightdriven proton pump of Halobacterium and to redox-coupled proton pumps in the mitochondrial respiratory chain. Similar considerations may be used to describe ATP-dependent ion transport. © 1979.