INFLUENCE OF THE SITE-DIRECTED MUTATIONS IN THE RETINAL ROD CGMP PHOSPHODIESTERASE GAMMA-SUBUNIT STRUCTURE ON ITS BINDING TO CATALYTIC SUBUNITS

Seven mutants of the cGMP phosphodiesterase gamma-subunit from bovine rod outer segments, translated in vitro in the wheat germ extract system, were chemically cross-linked with catalytic subunits in the disc membranes. The binding of the mutants to the membranes and formation of the cross-linked complexes was shown to correlate. Amino acid residues responsible for binding and inhibitory properties of the gamma-subunit were defined from the comparison of the results obtained and K(i) values for the same mutants.