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Journal of Bioenergetics and Biomembranes

, Volume 24, Issue 1, pp 27–31 | Cite as

Determination of the number of polypeptide subunits in a functional VDAC channel fromSaccharomyces cerevisiae

  • Songzhi Peng
  • Elizabeth Blachly-Dyson
  • Marco Colombini
  • Michael Forte
Research Paper

Abstract

Genes encoding VDAC proteins containing specific site-directed amino acid alterations were introduced into wild-typeSaccharomyces cerevisiae. The mutant VDAC proteins form channels with ion selectivities very different from that of the wild-type channel. Therefore, the resulting yeast strains express two different genes capable of coding for functional, yet distinct, VDAC channels. If VDAC were an oligomeric channel, analysis of VDAC from these strains should have revealed not only the presence of channels with wild-type or mutant selectivity but also channels with intermediate selectivities. While channels with wild-type and mutant selectivities were observed with approximately equal frequency, no channels with intermediate selectivity were observed. Sufficient observations were performed with two different mutant genes (K61E.K65E and K19E.K61E) that the likelihood of having missed hybrid channels was less than 1 in 107. These findings favor the hypothesis that each functional VDAC channel is composed of a single 30-kDa polypeptide chain.

Key words

Mitochondrion outer membrane voltage-gated channel site-directed mutations yeast hybrid 

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Copyright information

© Plenum Publishing Corporation 1992

Authors and Affiliations

  • Songzhi Peng
    • 1
  • Elizabeth Blachly-Dyson
    • 2
  • Marco Colombini
    • 1
  • Michael Forte
    • 2
  1. 1.Laboratories of Cell Biology, Department of ZoologyUniversity of MarylandCollege Park
  2. 2.Vollum Institute for Advanced Biomedical ResearchOregon Health Sciences UniversityPortland

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