In vitro synthesis, tetramerization and single channel characterization of virus-encoded potassium channel Kcv

Jiwook Shim, Mingming Yang, Li Qun Gu

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Chlorella virus-encoded membrane protein Kcv represents a new class of potassium channel. This 94-amino acids miniature K+ channel consists of two trans-membrane α-helix domains intermediated by a pore domain that contains a highly conserved K+ selectivity filter. Therefore, as an archetypal K+ channel, the study of Kcv may yield valuable insights into the structure-function relationships underlying this important class of ion channel. Here, we report a series of new properties of Kcv. We first verified Kcv can be synthesized in vitro. By co-synthesis and assembly of wild-type and the tagged version of Kcv, we were able to demonstrate a tetrameric stoichiometry, a molecular structure adopted by all known K+ channels. Most notably, the tetrameric Kcv complex retains its functional integrity in SDS (strong detergent)-containing solutions, a useful feature that allows for direct purification of protein from polyacrylamide gel. Once purified, the tetramer can form single potassium-selective ion channels in a lipid bilayer with functions consistent to the heterologously expressed Kcv. These finding suggest that the synthetic Kcv can serve as a model of virus-encoded K+ channels; and its newly identified properties can be applied to the future study on structure-determined mechanisms such as K+ channel functional stoichiometry.

Original languageEnglish (US)
Pages (from-to)1027-1034
Number of pages8
JournalFEBS Letters
Issue number5
StatePublished - Mar 6 2007


All Science Journal Classification (ASJC) codes

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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