The Active-site Environment of Rhodopsin

The active-site environment of rhodopsin.

The 11-cis-retinal binding site of rhodopsin is of great interest because it is buried in the membrane but yet must provide an environment for charged amino acids. In addition, the active-site lysine residue must be able to engage in rapid Schiff base formation with 11-cis-retinal at neutral and lower pH values. This requires that this lysine be unprotonated. We have begun to study the environm...

Active site-directed inactivation of constitutively active mutants of rhodopsin.

Recently, mutations of the active site Lys296 residue in rhodopsin (Lys296-->Glu and Lys296-->Met) have been found as the cause of disease in some patients with autosomal dominant retinitis pigmentosa. In vitro, these mutations result in constitutive activation of the protein. In an effort to develop a potential therapeutic agent for treatment of the disease, we have examined various amine deri...

PROBING THE ACTIVE SITE OF RHODANESE WITH DISULFIDE REAGENTS

Relocating the active-site lysine in rhodopsin and implications for evolution of retinylidene proteins.

Type I and type II rhodopsins share several structural features including a G protein-coupled receptor fold and a highly conserved active-site Lys residue in the seventh transmembrane segment of the protein. However, the two families lack significant sequence similarity that would indicate common ancestry. Consequently, the rhodopsin fold and conserved Lys are widely thought to have arisen from...

A convenient synthesis of labelled rhodopsin and studies on its active site.

Digitonin solutions of labelled rhodopsin, containing (3)H in the retinyl moiety, were prepared by two related methods. Labelled rhodopsin was also prepared for the first time in cetyltrimethylammonium bromide and purified by column chromatography. It was shown that only certain rhodopsin preparations on denaturation in the dark and the reduction with sodium borohydride gave up to 60% of the ra...