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Publication Abstract from PubMed

Microbial sensory rhodopsins are a family of membrane-embedded photoreceptors in prokaryotic and eukaryotic organisms. Structures of archaeal rhodopsins, which function as light-driven ion pumps or photosensors, have been reported. We present the structure of a eubacterial rhodopsin, which differs from those of previously characterized archaeal rhodopsins in its chromophore and cytoplasmic-side portions. Anabaena sensory rhodopsin exhibits light-induced interconversion between stable 13-cis and all-trans states of the retinylidene protein. The ratio of its cis and trans chromophore forms depends on the wavelength of illumination, thus providing a mechanism for a single protein to signal the color of light, for example, to regulate color-sensitive processes such as chromatic adaptation in photosynthesis. Its cytoplasmic half channel, highly hydrophobic in the archaeal rhodopsins, contains numerous hydrophilic residues networked by water molecules, providing a connection from the photoactive site to the cytoplasmic surface believed to interact with the receptor's soluble 14-kilodalton transducer.

Anabaena sensory rhodopsin: a photochromic color sensor at 2.0 A.,Vogeley L, Sineshchekov OA, Trivedi VD, Sasaki J, Spudich JL, Luecke H Science. 2004 Nov 19;306(5700):1390-3. Epub 2004 Sep 30. PMID:15459346^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.