Energy Transfer in Rhodopsin, N-Retinyl-Opsin, and Rod Outer Segments

AUTOR(ES)

Ebrey, Thomas G.

RESUMO

N-retinyl, the chromophore of bleached and reduced rhodopsin, N-retinyl-opsin, was used as a covalently attached fluorescence probe to examine the structure of N-retinyl-opsin and the rod outer segment. The efficiency of energy transfer from the protein part of N-retinyl-opsin to the chromophore is 12 ± 5%. It is argued that this implies that the N-retinyl-opsin molecule is asymmetrical. Kropf has estimated the efficiency of energy transfer from the protein to the chromophore in native rhodopsin to be about 50%. This difference of efficiencies seems to imply a large movement of the chromophore away from the tryptophans of the opsin after rhodopsin is bleached.

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