NeoR, a near-infrared absorbing rhodopsin

Matthias Broser*, Anika Spreen, Patrick E. Konold, Enrico Peter, Suliman Adam, Veniamin Borin, Igor Schapiro, Reinhard Seifert, John T.M. Kennis, Yinth Andrea Bernal Sierra, Peter Hegemann

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The Rhizoclosmatium globosum genome encodes three rhodopsin-guanylyl cyclases (RGCs), which are predicted to facilitate visual orientation of the fungal zoospores. Here, we show that RGC1 and RGC2 function as light-activated cyclases only upon heterodimerization with RGC3 (NeoR). RGC1/2 utilize conventional green or blue-light-sensitive rhodopsins (λmax = 550 and 480 nm, respectively), with short-lived signaling states, responsible for light-activation of the enzyme. The bistable NeoR is photoswitchable between a near-infrared-sensitive (NIR, λmax = 690 nm) highly fluorescent state (QF = 0.2) and a UV-sensitive non-fluorescent state, thereby modulating the activity by NIR pre-illumination. No other rhodopsin has been reported so far to be functional as a heterooligomer, or as having such a long wavelength absorption or high fluorescence yield. Site-specific mutagenesis and hybrid quantum mechanics/molecular mechanics simulations support the idea that the unusual photochemical properties result from the rigidity of the retinal chromophore and a unique counterion triad composed of two glutamic and one aspartic acids. These findings substantially expand our understanding of the natural potential and limitations of spectral tuning in rhodopsin photoreceptors.

Original languageEnglish
Article number5682
Pages (from-to)1-10
Number of pages10
JournalNature Communications
Volume11
Issue number1
Early online date10 Nov 2020
DOIs
Publication statusPublished - Dec 2020

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