Bacterial ion channels and their eukaryotic homologues

Due to the relative ease of obtaining their crystal structures, bacteria ion channels provide a unique opportunity to analyse structure and function of their eukaryotic homologues. This review describes prokaryotic channels whose structures have been determined. These channels are KcsA, a bacteria homologue of eukaryotic potassium channels, MscL, a bacterial mechanosensitive ion channel and ClC0, a prokaryotic homologue of the eukaryotic CIC family of anion-selective channels. General features of their structure and function are described with a special emphasis on the advantages that these channels offer for understanding the properties of their eukaryotic homologues. We present amino-acid sequences of eukaryotic proteins related in their primary sequences to bacterial mechanosensitive channels. The usefulness of bacterial mechanosensitive channels for the studies on general principles of mechanosensation is discussed. (C) 2001 John Wiley & Sons, Inc.