title: Ground state structure of D75N mutant of sensory rhodopsin II in complex with its cognate transducer.
abstract: The complex of sensory rhodopsin II (NpSRII) with its cognate transducer (NpHtrII) mediates negative phototaxis in halobacteria Natronomonas pharaonis. Upon light activation NpSRII triggers, by means of NpHtrII, a signal transduction chain homologous to the two component system in eubacterial chemotaxis. Here we report on the crystal structure of the ground state of the mutant NpSRII-D75N/NpHtrII complex in the space group I212121. Mutations of this aspartic acid in light-driven proton pumps dramatically modify or/and inhibit protein functions. However, in vivo studies show that the similar D75N mutation retains functionality of the NpSRII/NpHtrII complex. The structure provides the molecular basis for the explanation of the unexpected observation that the wild and the mutant complexes display identical physiological response on light excitation.
authors.affiliation: Institute of Complex Systems (ICS), ICS-5: Molecular Biophysics, Research Centre Juelich, 52425 Juelich, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Ishchenko
authors.forename: E
authors.initials: E
authors.lastname: Round
authors.forename: V
authors.initials: V
authors.lastname: Borshchevskiy
authors.forename: S
authors.initials: S
authors.lastname: Grudinin
authors.forename: I
authors.initials: I
authors.lastname: Gushchin
authors.forename: J P
authors.initials: JP
authors.lastname: Klare
authors.forename: T
authors.initials: T
authors.lastname: Balandin
authors.forename: A
authors.initials: A
authors.lastname: Remeeva
authors.forename: M
authors.initials: M
authors.lastname: Engelhard
authors.forename: G
authors.initials: G
authors.lastname: Büldt
authors.forename: V
authors.initials: V
authors.lastname: Gordeliy
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D002338:Carotenoids / Q000737:chemistry* / Q000235:genetics / Q000528:radiation effects; D018360:Crystallography, X-Ray; D006216:Halobacteriaceae / Q000737:chemistry; D025602:Halorhodopsins / Q000737:chemistry*; D006860:Hydrogen Bonding; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000235:genetics; D008027:Light; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000528:radiation effects; D025604:Rhodopsins, Microbial / Q000737:chemistry* / Q000235:genetics; D025603:Sensory Rhodopsins / Q000737:chemistry*; D015398:Signal Transduction
chemical_list: D019843:Archaeal Proteins; D025602:Halorhodopsins; C434451:HtrII protein, Natronobacterium pharaonis; D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D025604:Rhodopsins, Microbial; D025603:Sensory Rhodopsins; C434450:phototaxis receptor sensory rhodopsin II, Natronobacterium pharaonis; D002338:Carotenoids