• Medientyp: E-Artikel
  • Titel: NeoR, a near-infrared absorbing rhodopsin
  • Beteiligte: Broser, Matthias; Spreen, Anika; Konold, Patrick E.; Schiewer, Enrico; Adam, Suliman; Borin, Veniamin; Schapiro, Igor; Seifert, Reinhard; Kennis, John T. M.; Bernal Sierra, Yinth Andrea; Hegemann, Peter
  • Erschienen: Springer Science and Business Media LLC, 2020
  • Erschienen in: Nature Communications, 11 (2020) 1
  • Sprache: Englisch
  • DOI: 10.1038/s41467-020-19375-8
  • ISSN: 2041-1723
  • Entstehung:
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  • Beschreibung: <jats:title>Abstract</jats:title><jats:p>The <jats:italic>Rhizoclosmatium globosum</jats:italic> 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 (<jats:italic>λ</jats:italic><jats:sub>max</jats:sub> = 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, <jats:italic>λ</jats:italic><jats:sub>max</jats:sub> = 690 nm) highly fluorescent state (<jats:italic>Q</jats:italic><jats:sub>F</jats:sub> = 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.</jats:p>
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