On the conductance heterogeneity in membrane channels formed by gramicidin A. A cooperative study Academic Article uri icon


MeSH Major

  • Gramicidin
  • Lipid Bilayers


  • The relative frequency of low-conductance variants of gramicidin A channels in lipid bilayers was determined in parallel experiments in two different laboratories. A common gramicidin stock solution was tested in both labs and, initially, gave rise to significantly different proportions (9% v. 23%) of "mini" channels in the two labs. The lipid and gramicidin solutions were exchanged to identify the source of the difference: When using solutions prepared in lab A (Andersen), lab B (Busath) observed 9% minis, consistent with the original findings in lab A; when using the gramicidin solution prepared in lab B, lab A observed 18% minis, consistent with the original findings in lab B. The experimental apparatus and analysis techniques are therefore not the source of the discrepancy; rather, the difference appears to stem from some factor(s) related to the gramicidin, lipid, and electrolyte solutions. It appears that the mini frequency cannot reflect intrinsic characteristics of the channel-forming peptide, but rather must, at least in part, reflect environmental modulations of channel properties. This has implications for the interpretation of multi-channel experiments on gramicidin A.

publication date

  • January 1987



  • Academic Article



  • eng

PubMed Central ID

  • PMC1329865

PubMed ID

  • 2432954

Additional Document Info

start page

  • 79

end page

  • 88


  • 51


  • 1