Isolation of the Outer Membrane and Characterization of the Major Outer Membrane Protein from 'Spirochaeta aurantia'

摘要

The outer membrane of Spirochaeta aurantia was isolated after cells were extracted with sodium lauryl sarcosinate and was subsequently purified by differential centrifugation and potassium bromide isopycnic gradient centrifugation. The purified outer membrane was obtained in the form of carotenoid-containing vesicles. Four protein species were readily observed as components of the vesicles. Reconstitution of solubilized S. aurantia outer membrane into lipid bilayer membranes revealed the presence of a porin, presumably the 36.5K protein, with an estimated channel diameter of 2.3 nm.