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A Putative Prokaryote Voltage-Gated Ca2+ Channel with Only One 6TM Motif per Subunit,☆☆

https://doi.org/10.1006/bbrc.2001.4408Get rights and content

Abstract

Until now, voltage-gated Ca2+ 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 Ca2+ 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 Ca2+ channels originally evolved in bacteria, and that the specific eubacteria protein highlighted here is an ideal candidate for structure determination efforts.

References (28)

  • Y. Li-Smerin et al.

    A localized interaction surface for voltage-sensing domains on the pore domain of a K+ channel

    Neuron

    (2000)
  • B. Hille

    Ionic Channels of Excitable Membranes

    (1992)
  • M. Strong et al.

    Molecular evolution of voltage-sensitive ion channel genes: on the origins of electrical excitability

    Mol. Biol. Evol.

    (1993)
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    Abbreviation used: 6TM, 6-transmembrane segment.

    ☆☆

    To whom correspondence should be addressed at Laboratory of Experimental and Computational Biology, National Cancer Institute/National Institutes of Health, Building 12B, Room B116, 12 South Drive, Bethesda, MD 20892-5567. Fax: (301) 402-4724. E-mail: [email protected].

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