Structural Biology

Seeing the Light

Science's STKE  27 Jun 2000:
Vol. 2000, Issue 38, pp. tw6
DOI: 10.1126/stke.2000.38.tw6

Rhodopsin is a light-activated G protein-coupled receptor that induces the signaling cascade leading to vision. Isomerization of the 11-cis chromophore to all-trans triggers the visual transduction process. Borhan et al. have trapped the photoisomerization intermediates and have traced changes in the interaction between the chromophore and the protein by photoaffinity labeling. They show that the isomerization occurs with minimal movement of the chromophore ring, leading to a highly strained intermediate. This energy is used to flip the ring, which is accompanied by conformational changes in the protein.

Borhan, B., Souto, M.L., Imai, H., Shichida, Y., and Nakanishi, K. (2000) Movement of Retinal along the visual transduction path. Science 288: 2209-2212. [Abstract] [Full Text]