Channelrhodopsin-1: a light-gated proton channel in green algae.
Phototaxis and photophobic responses of green algae are mediated by rhodopsins with microbial-type chromophores. We report a complementary DNA sequence in the green alga Chlamydomonas reinhardtii that encodes a microbial opsin-related protein, which we term Channelopsin-1. The hydrophobic core region of the protein shows homology to the light-activated proton pump bacteriorhodopsin. Expression of Channelopsin-1, or only the hydrophobic core, in Xenopus laevis oocytes in the presence of all-trans retinal produces a light-gated conductance that shows characteristics of a channel selectively permeable for protons. We suggest that Channelrhodopsins are involved in phototaxis of green algae.
Nagel
Georg
G
Max-Planck-Institut für Biophysik, Kennedyallee 70, 60596 Frankfurt am Main, Germany. nagel@mpibp-frankfurt.mpg.de
Ollig
Doris
D
Fuhrmann
Markus
M
Kateriya
Suneel
S
Musti
Anna Maria
AM
Bamberg
Ernst
E
Hegemann
Peter
P
D000595:Amino Acid Sequence; D000818:Animals; D001436:Bacteriorhodopsins / Q000737:chemistry / Q000378:metabolism; D020148:Butyric Acid / Q000494:pharmacology; D016825:Chlamydomonas reinhardtii / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004553:Electric Conductivity; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017136:Ion Transport; D008027:Light; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D009865:Oocytes; D018408:Patch-Clamp Techniques; D011522:Protons; D018075:RNA, Complementary; D011994:Recombinant Proteins / Q000378:metabolism; D012172:Retinaldehyde / Q000494:pharmacology; D016415:Sequence Alignment; D013696:Temperature; D014982:Xenopus laevis
D007473:Ion Channels; D011522:Protons; D018075:RNA, Complementary; D011994:Recombinant Proteins; D020148:Butyric Acid; D001436:Bacteriorhodopsins; D012172:Retinaldehyde