The electrostatic and shape complementarities between the crystal structures of dark rhodopsin and heterotrimeric transducin (Gt) have been evaluated by exhaustively sampling the roto-translational space of one protein with respect to the other. Structural complementarity, reliability, and consistency with in vitro evidence all converge in the same rhodopsin-Gt complex, showing that the functionally important R135 of the E/DRY motif is almost accessible to the C-terminus of Gt already in the dark state. The main inference from this study is that activation of rhodopsin and Gt may be concurrent processes, consisting of conformational changes in a supramolecular complex formed prior to the light-induced activation of the photoreceptor.
Rhodopsin activation follows precoupling with transducin: inferences from computational analysis.
DELL'ORCO, Daniele
2005-01-01
Abstract
The electrostatic and shape complementarities between the crystal structures of dark rhodopsin and heterotrimeric transducin (Gt) have been evaluated by exhaustively sampling the roto-translational space of one protein with respect to the other. Structural complementarity, reliability, and consistency with in vitro evidence all converge in the same rhodopsin-Gt complex, showing that the functionally important R135 of the E/DRY motif is almost accessible to the C-terminus of Gt already in the dark state. The main inference from this study is that activation of rhodopsin and Gt may be concurrent processes, consisting of conformational changes in a supramolecular complex formed prior to the light-induced activation of the photoreceptor.
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