A putative prokaryote voltage-gated Ca(2+) channel with only one 6TM motif per subunit.
Until now, voltage-gated Ca(2+) channel proteins have been found only in eukaryotes. Here we report that a gene recently discovered in the eubacterium Bacillus halodurans codes for a protein closely related to eukaryotic Ca(2+) channels, but that has only one 6-transmembrane-segement (6TM) motif, instead of four, in its pore-forming subunit. This is supported by the comparison of consensus sequences, which, along with the patterns of residue conservation, indicates a similar structure in the membrane to voltage-gated K(+) channels. From this we hypothesize that Ca(2+) channels originally evolved in bacteria, and that the specific eubacteria protein highlighted here is an ideal candidate for structure determination efforts.
Molecular Structure Section, Laboratory of Experimental and Computational Biology, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland, 20892, USA.
S R
SR
Durell
H R
HR
Guy
D000595:Amino Acid Sequence; D015220:Calcium Channels / Q000737:chemistry*; D015640:Ion Channel Gating; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D015220:Calcium Channels