[Molecular basis of ion selectivity based on crystalline structure of bacterial channels].

Unlabelled: The principles of ionic selectivity of the two crystallised bacterial ion channels are described. These channels are: the potassium channel KcsA, whose amino-acid sequence is homologous to the eukaryotic voltage--dependent potassium channels and the chloride channel EcClC that is a prokaryotic member of the ClC family of chloride channels.

In Conclusion: although the overall molecular architecture of KcsA is different from that of EcClC, the selectivity filters in both cases show similarities. They both utilise helix dipoles organised within the channel molecule in such a fashion to produce electrostatically favourable environment for anions (in the case of EcClC) or cations (in the case of KcsA).