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Issue 2, 2010
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The DC gate in Channelrhodopsin-2: crucial hydrogen bonding interaction between C128 and D156

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Abstract

The light-gated cation channel Channelrhodopsin-2 (ChR2), a retinylidene protein found in the eye-spot of Chlamydomonas reinhardtii, became an optogenetic tool to trigger neurophysiological responses by light and, thus, revolutionized spatio-temporal studies of such processes. The reaction mechanism still remains elusive but recent vibrational spectroscopic experiments started to resolve details of the associated structural changes during the photocycle. Large alterations in the polypeptide backbone were observed by FT-IR spectroscopy that precede and succeed the opening and closing of the channel, respectively. However, the molecular switch that controls gating is still unknown. Here, we present difference spectra of the D156E mutant of ChR2 and assign the observed vibrational bands to crucial hydrogen bonding changes of this residue in various intermediate states of the photoreaction. By comparison with spectra of wild-type ChR2 and the C128T mutant and correlation to electrophysiological studies, we propose the DC gate as a crucial hydrogen-bonding interaction between D156 and C128 which may represent the valve of the channel.

Graphical abstract: The DC gate in Channelrhodopsin-2: crucial hydrogen bonding interaction between C128 and D156

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Publication details

The article was received on 04 Nov 2009, accepted on 23 Nov 2009 and first published on 07 Jan 2010


Article type: Paper
DOI: 10.1039/B9PP00157C
Citation: Photochem. Photobiol. Sci., 2010,9, 194-198
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    The DC gate in Channelrhodopsin-2: crucial hydrogen bonding interaction between C128 and D156

    M. Nack, I. Radu, M. Gossing, C. Bamann, E. Bamberg, G. F. von Mollard and J. Heberle, Photochem. Photobiol. Sci., 2010, 9, 194
    DOI: 10.1039/B9PP00157C

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