Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Bacteriorhodopsins / chemistry
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Bacteriorhodopsins / metabolism
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Butyric Acid / pharmacology
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Chlamydomonas reinhardtii / chemistry
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Chlamydomonas reinhardtii / genetics
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Chlamydomonas reinhardtii / metabolism*
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Electric Conductivity
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Hydrogen-Ion Concentration
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Ion Channel Gating
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Ion Channels / chemistry*
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Ion Channels / genetics
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Ion Channels / metabolism*
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Ion Transport
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Light*
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Membrane Potentials
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Molecular Sequence Data
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Oocytes
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Patch-Clamp Techniques
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Protons*
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RNA, Complementary
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Recombinant Proteins / metabolism
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Retinaldehyde / pharmacology
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Sequence Alignment
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Temperature
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Xenopus laevis
Substances
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Ion Channels
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Protons
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RNA, Complementary
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Recombinant Proteins
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Butyric Acid
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Bacteriorhodopsins
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Retinaldehyde