Structural highlights
Function
[BACS2_NATPH] Involved in the control of phototaxis. Seems to activate a methyl-accepting protein (HTR-II). Photoreceptor for blue light. [HTR2_NATPH] Transduces signals from the phototaxis receptor sensory rhodopsin II (SR-II) to the flagellar motor. Responds to light changes through the variation of the level of methylation. Also acts as a chemotransducer.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Microbial rhodopsins, which constitute a family of seven-helix membrane proteins with retinal as a prosthetic group, are distributed throughout the Bacteria, Archaea and Eukaryota. This family of photoactive proteins uses a common structural design for two distinct functions: light-driven ion transport and phototaxis. The sensors activate a signal transduction chain similar to that of the two-component system of eubacterial chemotaxis. The link between the photoreceptor and the following cytoplasmic signal cascade is formed by a transducer molecule that binds tightly and specifically to its cognate receptor by means of two transmembrane helices (TM1 and TM2). It is thought that light excitation of sensory rhodopsin II from Natronobacterium pharaonis (SRII) in complex with its transducer (HtrII) induces an outward movement of its helix F (ref. 6), which in turn triggers a rotation of TM2 (ref. 7). It is unclear how this TM2 transition is converted into a cellular signal. Here we present the X-ray structure of the complex between N. pharaonis SRII and the receptor-binding domain of HtrII at 1.94 A resolution, which provides an atomic picture of the first signal transduction step. Our results provide evidence for a common mechanism for this process in phototaxis and chemotaxis.
Molecular basis of transmembrane signalling by sensory rhodopsin II-transducer complex.,Gordeliy VI, Labahn J, Moukhametzianov R, Efremov R, Granzin J, Schlesinger R, Buldt G, Savopol T, Scheidig AJ, Klare JP, Engelhard M Nature. 2002 Oct 3;419(6906):484-7. PMID:12368857[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Gordeliy VI, Labahn J, Moukhametzianov R, Efremov R, Granzin J, Schlesinger R, Buldt G, Savopol T, Scheidig AJ, Klare JP, Engelhard M. Molecular basis of transmembrane signalling by sensory rhodopsin II-transducer complex. Nature. 2002 Oct 3;419(6906):484-7. PMID:12368857 doi:10.1038/nature01109
