Vibronic dynamics of the ultrafast all-trans to 13-cis photoisomerization of retinal in channelrhodopsin-1

Journal article

Channelrhodopsins are light-gated ion channels with extensive applications in optogenetics. Channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) exhibits a red-shifted absorption spectrum as compared to Channelrhodopsin-2, which is highly beneficial for optogenetic application. The primary event in the photocycle of CaChR1 involves an isomerization of the protein-bound retinal chromophore. Here, we apply highly time-resolved vibronic spectroscopy to reveal the electronic and structural dynamics associated with the first step of the photocycle of CaChR1. We observe vibrationally coherent formation of the P1 intermediate exhibiting a twisted 13-cis retinal with a 110 ± 7 fs time constant. Comparison with low-temperature resonance Raman spectroscopy of the corresponding trapped photoproduct demonstrates that this rapidly formed P1 intermediate is stable for several hundreds of nanoseconds.

Authors: Schnedermann, C; Muders, V; Ehrenberg, D; Schlesinger, R; Kukura, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: Journal of the American Chemical Society
• Volume: 138
• Issue: 14
• Pages: 4757–4762
• Publication date: 2016-03-21
• DOI: 10.1021/jacs.5b12251
• ISSN: 0002-7863 and 1520-5126
• Pmid: 26999496
• Language: English
• Keywords: SBTMR