title: NaChBac: the long lost sodium channel ancestor.
abstract: In excitable cells, the main mediators of sodium conductance across membranes are voltage-gated sodium channels (Na(V)s). Eukaryotic Na(V)s are essential elements in neuronal signaling and muscular contraction and in humans have been causally related to a variety of neurological and cardiovascular channelopathies. They are complex heavily glycosylated intrinsic membrane proteins present in only trace quantities that have proven to be challenging objects of study. However, in recent years, a number of simpler prokaryotic sodium channels have been identified, with NaChBac from Bacillus halodurans being the most well-characterized to date. The availability of a bacterial Na(V) that is amenable to heterologous expression and functional characterization in both bacterial and mammalian systems has provided new opportunities for structure--function studies. This review describes features of NaChBac as an exemplar of this class of bacterial channels, compares prokaryotic and eukaryotic Na(V)s with respect to their structural organization, pharmacological profiling, and functional kinetics, and discusses how voltage-gated ion channels may have evolved to deal with the complex functional demands of higher organisms.
authors.affiliation: Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, UK.
authors.forename: Kalypso
authors.initials: K
authors.lastname: Charalambous
authors.forename: B A
authors.initials: BA
authors.lastname: Wallace
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000737:chemistry*; D006031:Glycosylation; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D015222:Sodium Channels