Pore forming activity of the major outer membrane protein of Rhodobacter capsulatus in lipid bilayer membranes

摘要: Porin of the outer membrane Rhodobacter capsulatus St. Louis (ATCC 23782) was isolated and reconstituted into lipid bilayer membranes. The porin obtained either by sodium dodecyl sulfate treatment cell envelopes (SDS-porin) or saline extraction whole cells (NaCl-porin). Nanomolar concentrations both preparations resulted in a strong conductance increase membranes many orders magnitude. At small protein increased stepwise fashion, average single channel being about 0.35 nS 0.1 M KCl for SDS-porin NaCl-porin as well. linear function specific aqueous phase. results were consistent with assumption that formed large water-filled transmembrane channels membrane. From value an effective diameter 1.5 nm estimated types porins.