ArticlePhotochemistry and photobiology2020
Analog Retinal Redshifts Visible Absorption of QuasAr Transmembrane Voltage Sensors into Near-infrared.
Article in Photochemistry and photobiology, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
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Who cites it
6 citing papers in PubMed, 12 citations in OpenAlex.
- Plasmonic Enhancement of Fluorescence and Protein Dynamics in Living Mammalian Cells.Advanced materials (Deerfield Beach, Fla.) · 2026Article
- Reinvestigation of Absorption Spectroscopic Thermal Dynamics of Archaerhodopsin 3 Based Voltage Sensor QuasAr1.Bioengineering (Basel, Switzerland) · 2025Article
- Merocyanines form bacteriorhodopsins with strongly bathochromic absorption maxima.Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology · 2024Article
- Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering.Frontiers in chemistry · 2022Review
- Optical Switching Between Long-lived States of Opsin Transmembrane Voltage Sensors.Photochemistry and photobiology · 2021Article
- Exploring the Retinal Binding Cavity of Archaerhodopsin-3 by Replacing the Retinal Chromophore With a Dimethyl Phenylated Derivative.Frontiers in molecular biosciences · 2021Article
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Authors and funding
6 authors at 3 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Opsin-based transmembrane voltage sensors (OTVSs) are increasingly important tools for neuroscience enabling neural function in complex brain circuits to be explored in live, behaving animals. However, the visible wavelengths required for fluorescence excitation of the current generation of OTVSs limit optogenetic imaging in the brain to depths of only a few mm due to the strong absorption and scattering of visible light by biological tissues. We report that substitution of the native A1 retinal chromophore of the widely used QuasAr1/2 OTVSs with the retinal analog MMAR containing a methylamino-modified dimethylphenyl ring results in over a 100-nm redshift of the maxima of the absorption and fluorescence emission bands to near 700 and 840 nm, respectively. FT-Raman spectroscopy reveals that at pH 7 QuasAr1 with both the A1 and MMAR chromophores possess predominantly an all-trans protonated Schiff base configuration with the MMAR chromophore exhibiting increased torsion of the polyene single-/double-bond system similar to the O-intermediate of the BR photocycle. In contrast, the A1 and the MMAR chromophores of QuasAr2 exist partially in a 13-cis PSB configuration. These results demonstrate that QuasArs containing the MMAR chromophore are attractive candidates for use as NIR-OTVSs, especially for applications such as deep brain imaging.
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