On the function and structure of synthetically modified porins.

The attachment of modulators to a trimeric porin ion channel was investigated (see picture of the trimer with a crown ether modulator (orange)). The interplay of modulator and protein is essential for the conformational heterogeneity of the hybrid channel. Single-site attachment in large pores is not sufficient to change the electrophysiological characteristics of the pores-such change requires additional noncovalent interactions or second-site attachments.