Essentiality of the molecular weight 15,000 protein (subunit IV) in the cytochrome b-c1 complex of Rhodobacter sphaeroides.

The cytochrome b-c 1 complex from Rhodobacter sphaeroides was resolved into four protein subunits by a phenyl-Sepharose CL-4B column eluted with different detergents. Individual subunits were purified to homogeneity. Antibodies against subunit IV (M r =15000) were raised and purified. These antibodies had a high titer with isolated subunit IV and with the b-c 1 complex from R. sphaeroides