Amino terminal of the G-protein receptor rhodopsin
Rhodopsin is the archetypal G-protein-coupled receptor. Such receptors participate in virtually all physiological processes, as signalling molecules. They utilize heterotrimeric guanosine triphosphate (GTP)-binding proteins to transduce extracellular signals to intracellular events. Rhodopsin is important because of the pivotal role it plays in visual signal transduction. Rhodopsin is a dimeric transmembrane protein and its intradiskal surface consists of this amino terminal domain and three loops connecting six of the seven transmembrane helices. The N-terminus is a compact domain of alpha-helical regions with breaks and bends at proline residues outside the membrane. The transmembrane part of rhodopsin is represented by 7tm_1 (pfam00001). The N-terminal domain is extracellular is and is necessary for successful dimerization and molecular stability.
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