title: Sulfhydryl group modification of photoreceptor G-protein prevents its light-induced binding to rhodopsin.
abstract: The effect of sulfhydryl modification on the light-induced interaction between rhodopsin and the peripheral GTP-binding protein of the photoreceptor membrane (G-protein) has been investigated by time-resolved near-infrared light-scattering and polyacrylamide gel electrophoresis. It has been found that the modification of rhodopsin with the alkylating agent N-ethylmaleimide (NEM) does not affect its light-induced interaction with the G-protein. Modification of G-protein with NEM or other sulfhydryl agents prevents any light-induced binding to rhodopsin. Dark-association of G to the membrane as well as the light-induced complex with rhodopsin (once formed) is insensitive to NEM.
mesh_terms: D000478:Alkylation; D000818:Animals; D002417:Cattle; D005033:Ethylmaleimide / Q000494:pharmacology; D005136:Eye Proteins / Q000378:metabolism*; D020962:Heterotrimeric GTP-Binding Proteins; D008027:Light; D010786:Photoreceptor Cells / Q000502:physiology*; D011485:Protein Binding; D012168:Retinal Pigments / Q000378:metabolism*; D012243:Rhodopsin / Q000378:metabolism*; D012374:Rod Cell Outer Segment / Q000502:physiology*; D013055:Spectrophotometry, Infrared; D015293:Transducin
chemical_list: D005136:Eye Proteins; C034809:GNAT1 protein, human; D012168:Retinal Pigments; D012243:Rhodopsin; D020962:Heterotrimeric GTP-Binding Proteins; D015293:Transducin; D005033:Ethylmaleimide