INVESTIGATIONS ON MEMBRANE PROTEINS IN RHODOSPIRILLUM RUBRUM

Membrane fractions from aerobically dark-grown Rhodospirillum rubrum and chromatophores (=thylakoids) were split into their protein subunits by phenol-urea-acetic acid (2:1.2:1, w/w/v) and separated by polyacrylamide gel electrophoresis. The spectra of the proteins of both types of membranes differed only slightly. A fraction was isolated from chromatophores (=thylakoids) by the methods for the homogeneous mitochondrial structural protein. When this fraction was split by phenol-urea-acetic acid and separated by gel electrophoresis several proteins could be identified. All of these proteins were soluble in 8 M urea. The consequences of these findings are discussed with respect to the composition of membranes in Rhodospirillum rubrum. © 1969 Springer-Verlag.