title: Eukaryotic G protein-coupled receptors as descendants of prokaryotic sodium-translocating rhodopsins.
abstract: Microbial rhodopsins and G-protein coupled receptors (GPCRs, which include animal rhodopsins) are two distinct (super) families of heptahelical (7TM) membrane proteins that share obvious structural similarities but no significant sequence similarity. Comparison of the recently solved high-resolution structures of the sodium-translocating bacterial rhodopsin and various Na(+)-binding GPCRs revealed striking similarity of their sodium-binding sites. This similarity allowed us to construct a structure-guided sequence alignment for the two (super)families, which highlighted their evolutionary relatedness. Our analysis supports a common underlying molecular mechanism for both families that involves a highly conserved aromatic residue playing a pivotal role in rotation of the 6th transmembrane helix.
authors.affiliation: School of Physics, Osnabrueck University, 49069, Osnabrueck, Germany. dshalaeva@uni-osnabrueck.de.|School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia. dshalaeva@uni-osnabrueck.de.
authors.forename: Daria N
authors.initials: DN
authors.lastname: Shalaeva
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA. galperin@ncbi.nlm.nih.gov.
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Galperin
authors.affiliation: School of Physics, Osnabrueck University, 49069, Osnabrueck, Germany. amulkid@uos.de.|School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia. amulkid@uos.de.|A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia. amulkid@uos.de.
authors.forename: Armen Y
authors.initials: AY
authors.lastname: Mulkidjanian
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D056890:Eukaryota / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D025604:Rhodopsins, Microbial / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D012964:Sodium / Q000378:metabolism
chemical_list: D043562:Receptors, G-Protein-Coupled; D025604:Rhodopsins, Microbial; D012964:Sodium