Many processes in green algae are under control of rhodopsin-type photoreceptors, but only a few have been studied at least in some detail in the past. Up to now, functionally and biochemically only the channelrhodpsins ChR1 and ChR2 are characterized. Thus, this short review reports on channelrhodopsin properties with a strong focus on the knowledge about the photoreaction cycle(s).
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http://dx.doi.org/10.1002/cphc.200900980 | DOI Listing |
J Neurosci
December 2024
Dept. Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260
The mammalian auditory system encodes sounds with subtypes of spiral ganglion neurons (SGNs) that differ in sound level sensitivity, permitting discrimination across a wide range of levels. Recent work suggests the physiologically-defined SGN subtypes correspond to at least three molecular subtypes. It is not known how information from the different subtypes converges within the cochlear nucleus.
View Article and Find Full Text PDFJ Mol Biol
December 2024
The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan. Electronic address:
Channelrhodopsins are light-gated ion channels consisting of seven transmembrane helices and a retinal chromophore, which are used as popular optogenetic tools for modulating neuronal activity. Cation channelrhodopsins (CCRs), first recognized as the photoreceptors in the chlorophyte Chlamydomonas reinhardtii, have since been identified in diverse species of green algae, as well in other unicellular eukaryotes. The CCRs from non-chlorophyte species are commonly referred to as bacteriorhodopsin-like cation channelrhodopsins, or BCCRs, as most of them feature the three characteristic amino acid residues of the "DTD motif" in the third transmembrane helix (TM3 or helix C) matching the canonical DTD motif of the well-studied archaeal light-driven proton pump bacteriorhodopsin.
View Article and Find Full Text PDFElife
October 2024
Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany.
Channelrhodopsins (ChRs) are light-gated ion channels widely used to optically activate or silence selected electrogenic cells, such as individual brain neurons. Here, we describe identifying and characterizing a set of anion-conducting ChRs (ACRs) from diverse taxa and representing various branches of the ChR phylogenetic tree. The ACR (MsACR1) showed high sensitivity to yellow-green light ( at 555 nm) and was further engineered for optogenetic applications.
View Article and Find Full Text PDFBiophys J
June 2024
Department of Chemistry & Biochemistry, University of California, Santa Cruz, Santa Cruz, California. Electronic address:
The light-gated anion channelrhodopsin GtACR1 is an important optogenetic tool for neuronal silencing. Its photochemistry, including its photointermediates, is poorly understood. The current mechanistic view presumes BR-like kinetics and assigns the open channel to a blue-absorbing L intermediate.
View Article and Find Full Text PDFBiophys J
April 2024
Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California. Electronic address:
Anion channelrhodopsin GtACR1 is a powerful optogenetic tool to inhibit nerve activity. Its kinetic mechanism was interpreted in terms of the bacteriorhodopsin photocycle, and the L intermediate was assigned to the open channel state. Here, we report the results of the comparison between the time dependence of the channel currents and the time evolutions of the K-like and L-like spectral forms.
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