Structure and Function of Visual Rhodopsins

The role of visual rhodopsins is to activate transducin, a heterotrimeric G protein, in the signal transduction cascade of vision [6,7,24]. Rhodopsin, a member of the 

18 amino acids and a water are shown that have atoms within 4.0 A from the retinal chromophore. 

Previous site-directed mutagenesis revealed glutamate at position 113 (E113) to be the counterion in bovine rhodopsin (Fig. 4.4), which was determined by the 

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