Subunit composition of the high conductance calcium-activated potassium channel from smooth muscle, a representative of the mSlo and slowpoke family of potassium channels.

摘要: High conductance Ca(2+)-activated K+ (maxi-K) channels from bovine tracheal and aortic smooth muscle membranes have been purified employing monoiodotyrosine charybdotoxin binding as a marker for the channel conventional chromatographic techniques. This is composed of two subunits, alpha beta, 62 31 kDa, respectively. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis, electroeluted alpha-subunit was subjected to tryptic cleavage number fragments were isolated by microbore C18 high performance liquid chromatography. Several these peptides microsequenced using Edman degradation Amino acid sequence information obtained reveals existence very homology with recently cloned mSlo maxi-K (Butler, A., Tsunoda, S., McCobb, D. P., Wei, Salkoff, L. (1993) Science 261, 221-224). A specific anti-peptide antibody directed against amino one capable specifically immunoprecipitating not only denatured 125I-Bolton-Hunter-labeled alpha-subunit, but also, under nondenaturing conditions, complex beta demonstrating noncovalent association both subunits. Thus, our results indicate that member family forms beta-subunit. It concluded extensive biochemical acquired date on receptors pertinent structure native channels.