[The effect of proteolytic removal of the C-terminal fragment of rhodopsin on its ability to activate visual cascade].
The role of the C-terminal domain of rhodopsin in the activation of transducin was studied. The treatment of photoreceptor membranes with trypsin, thermolysin, and Asp-N-endoprotease led to the respective rhodopsin species devoid of 9, 12-, or 19-aa C-terminal fragments. It was shown that the removal of 9-aa fragment by trypsin does not affect the catalytic activity of the receptor, whereas the thermolysin-induced truncation of the rhodopsin C-terminus by 12 aa about 1.5-fold enhances its activity. The Asp-N-endoprotease-assisted removal of 19 aa (i.e., the shortening by seven more C-terminal aa) virtually unchanges the rhodopsin catalytic activity compared to the preparation truncated with thermolysin. These results suggest that the part of the rhodopsin C-terminal fragment between the sites of its cleavage by trypsin and thermolysin (Val337-Ser338-Lys339) inhibits the signal transduction from rhodopsin to the next component of visual cascade. The English version of the paper.
Komolov
K E
KE
Department of Enzymology, Belozerskii Research Institute of Physicochemical Biology, Moscow State University, Vorob'evy gory, Moscow, 119899 Russia.
Senin
I I
II
Filippov
P P
PP
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D006152:Cyclic GMP; D010450:Endopeptidases / Q000378:metabolism; D005136:Eye Proteins; D051606:G-Protein-Coupled Receptor Kinase 1; D008666:Metalloendopeptidases; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D012243:Rhodopsin / Q000737:chemistry* / Q000378:metabolism*; D015398:Signal Transduction; D013820:Thermolysin / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
D005136:Eye Proteins; D010446:Peptide Fragments; D012243:Rhodopsin; D011494:Protein Kinases; D051606:G-Protein-Coupled Receptor Kinase 1; D010450:Endopeptidases; D014357:Trypsin; D008666:Metalloendopeptidases; D013820:Thermolysin; C058921:endoproteinase Asp-N; D006152:Cyclic GMP