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. Author manuscript; available in PMC: 2010 May 25.
Published in final edited form as: Biochem J. 2010 Apr 28;428(1):1–10. doi: 10.1042/BJ20100270

Figure 1. Schematic diagram of the reaction pathway for Gt activation.

Figure 1

Light causes transition of dark state Rho to activated Rho* that binds heterotrimeric GtαGDPβγ. This binding induces GDP release from the Gt nucleotide-binding pocket and formation of the transient nucleotide-free Rho*–Gtαeβγ complex. Uptake of GTP then leads to formation of the Rho*–GtαGTPβγ complex with subsequent release and dissociation of GtαGTP and Gtβγ from Rho*. Free Rho* then decays to opsin and all-trans-retinal. Subsequent uptake of 11-cis-retinal completes the cycle by regenerating Rho.