G proteins couple receptors of extracellular signals to intracellular signaling pathways. The G protein alpha subunit binds guanyl nucleotide and is a weak GTPase. A set of residues that are unique to G-alpha as compared to its ancestor the Arf-like ...
G proteins couple receptors of extracellular signals to intracellular signaling pathways. The G protein alpha subunit binds guanyl nucleotide and is a weak GTPase. A set of residues that are unique to G-alpha as compared to its ancestor the Arf-like family form a ring of residues centered on the nucleotide binding site [3]. A Ggamma is found fused to an inactive Galpha in the Dictyostelium protein gbqA [3].
This family contains, amongst other G-protein-coupled receptors (GCPRs), members of the opsin family, which have been considered to be typical members of the rhodopsin superfamily. They share several motifs, mainly the seven transmembrane helices, GC ...
This family contains, amongst other G-protein-coupled receptors (GCPRs), members of the opsin family, which have been considered to be typical members of the rhodopsin superfamily. They share several motifs, mainly the seven transmembrane helices, GCPRs of the rhodopsin superfamily. All opsins bind a chromophore, such as 11-cis-retinal. The function of most opsins other than the photoisomerases is split into two steps: light absorption and G-protein activation. Photoisomerases, on the other hand, are not coupled to G-proteins - they are thought to generate and supply the chromophore that is used by visual opsins [1].
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 utilise heterotrimeric guanosine triphosphate (GTP)-binding proteins to transduce extracellular ...
Rhodopsin is the archetypal G-protein-coupled receptor. Such receptors participate in virtually all physiological processes, as signalling molecules. They utilise 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 [1]. The transmembrane part of rhodopsin is represented by 7tm_1 (Pfam:PF00001). The N-terminal domain is extracellular is and is necessary for successful dimerisation and molecular stability [2].
