Proteins of R. spheroides Y reaction center: Gel electrophoresis and electrofocusing studies

Abstract

Summary The reaction center preparation isolated from R. spheroides Y was analyzed by polyacrylamide gel electrophoresis and gel electrofocusing procedures. Prior to electrofocusing it migrated in at most two bands, either in presence of detergent or of urea-phenol-acetic acid mixtures. In the presence of SDS, the protein bands were split into 4 subunits (Mw respectively 12 000, 30 000, 61 000 and 74 000). The band at Mw 30 000 was the major component. After gel electrofocusing, a reaction center particle (pI = 6.5) retaining activity was isolated; it contained only the 30 000 Mw subunit. It is proposed that the protein binding the pigment in the native reaction center is either the monomer, or the dimer of this subunit.