期刊
NATURE CHEMISTRY
卷 14, 期 4, 页码 441-+出版社
NATURE PORTFOLIO
DOI: 10.1038/s41557-022-00892-6
关键词
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资金
- NSF [CHE-CLP-1710191]
- NIH [GM126627-01, USIAS 2015]
- Ohio Supercomputer Center
- Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR)
- Fondazione Banca d'Italia (as part of the ITI 2021-2028 program of the University of Strasbourg)
- CNRS
- Inserm via the IdEx Unistra project of the French Investments for the Future Program [ANR 10 IDEX 0002]
- Inserm via SFRI STRAT'US project of the French Investments for the Future Program [ANR 20 SFRI 0012]
- Inserm via project of the French Investments for the Future Program [ANR-11-LABX-0058_NIE]
This study demonstrates the degeneracy between the reactive excited state and a neighboring state in rhodopsin, which causes the splitting of the rhodopsin population into subpopulations after 15 femtoseconds of light absorption. These subpopulations propagate with different velocities and contribute differently to the quantum efficiency. Furthermore, the study reveals that protein electrostatics modulate this splitting and link amino acid sequence variations to quantum efficiency modulation.
The activation of rhodopsin, the light-sensitive G-protein-coupled receptor responsible for dim-light vision in vertebrates, is driven by an ultrafast excited-state double-bond isomerization with a quantum efficiency of almost 70%. The origin of such light sensitivity is not understood and a key question is whether in-phase nuclear motion controls the quantum efficiency value. In this study we used hundreds of quantum-classical trajectories to show that, 15 fs after light absorption, a degeneracy between the reactive excited state and a neighbouring state causes the splitting of the rhodopsin population into subpopulations. These subpopulations propagate with different velocities and lead to distinct contributions to the quantum efficiency. We also show here that such splitting is modulated by protein electrostatics, thus linking amino acid sequence variations to quantum efficiency modulation. Finally, we discuss how such a linkage that in principle could be exploited to achieve higher quantum efficiencies would simultaneously increase the receptor thermal noise leading to a trade-off that may have played a role in rhodopsin evolution.
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