Fig. 1
From: High frequency neural spiking and auditory signaling by ultrafast red-shifted optogenetics
Channelrhodopsin mutants with accelerated closing kinetics. a Helix F and helix C of channelrhodopsin48. Residues changing the off-kinetics are highlighted (ChR2 numbering). b ClustalW alignment ot the helix F of ChR2, Chrimson, ReaChR and VChR1. Colored boxes show the channelrhodopsin mutants. c–h NG cells heterologously expressing channelrhodopsin variants were investigated by whole-cell patch-clamp experiments at a membrane potential of −60 mV. Typical photocurrents of ChR2-EYFP (black trace), ChR2-EYFP F219Y (red trace) (c), VChR1-EYFP (black trace), VChR1-EYFP F214Y (red trace) (d), ReaChR-Citrine (black trace), ReaChR-Citrine F259Y (red trace) (e), Chrimson-EYFP (black trace) and Chrimson-EYFP Y261F (red trace) (f) immediately after cessation of 0.5 s illumination at a saturating light intensity of 23 mW/mm-2 and a wavelength of c λ = 473 nm, d λ = 532 nm, e λ = 532 nm and f λ = 594 nm. g Typical photocurrents of Chrimson-EYFP mutants, which were measured in response to 3 ms light-pulses (23 mW/mm2, λ = 594 nm). h For clear illustration solely the photocurrents of Chrimson-EYFP, Chrimson-EYFP Y261F/S267M (f-Chrimson-EYFP) and Chrimson-EYFP K176R/Y261F/S267M (vf-Chrimson-EYFP) are shown. Photocurrents were normalized for comparison. Scale bars: c 10 ms, d, f 30 ms, e 100 ms, g, h 20 ms
