Asymmetry of an energy transducing membrane. The location of cytochrome c2 in Rhodopseudomonas spheroides and Rhodopseudomonas capsulata

Monospecific antibodies have been prepared against cytochrome c₂ from Rhodopseudomonas spheroides and Rhodopseudomonas capsulata, and against cytochrome c′ from Rps. capsulata. These antibodies precipitated their respective antigens, but did not cross react with a wide range of procaryotic or eucaryotic cytochromes, or with other bacterial proteins. The cytochromes produced during aerobic growth were immunologically indistinguishable from those produced during photosynthetic growth.Cytochrome c₂ is located in vivo in the periplasmic space between the cell wall and the cell membrane, and when chromatophores are prepared from whole cells the cytochrome becomes trapped inside these vesicles. The implications of these results to energy coupling in the photosynthetic bacteria are discussed.