Few-fs resolution of a photoactive protein traversing a conical intersection

• Published in: Nature (London) Vol. 599; no. 7886; pp. 697 - 701
• Main Authors: Hosseinizadeh, A, Breckwoldt, N, Fung, R, Sepehr, R, Schmidt, M, Schwander, P, Santra, R, Ourmazd, A
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 25.11.2021
• Subjects: Accuracy; Approximation; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Biological research; Biology, Experimental; Chemical properties; Crystallography; Crystalloids (Botany); Deoxyribonucleic acid; DNA; Electrons; Energy; Excitation; Funnels; Geometry; Intersections; Isomerism; Learning algorithms; Machine Learning; Methods; Molecular dynamics; Photoactive yellow protein; Photoreceptors, Microbial - chemistry; Photoreceptors, Microbial - metabolism; Photosynthesis; Potential energy; Proteins; Quantum Theory; Reproducibility of Results; Science & Technology - Other Topics; Spectroscopy; Spectrum Analysis; Time Factors; Time series; Topography; Video; Yellow protein; Germany
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-021-04050-9

The structural dynamics of a molecule are determined by the underlying potential energy landscape. Conical intersections are funnels connecting otherwise separate potential energy surfaces. Posited almost a century ago , conical intersections remain the subject of intense scientific interest . In biology, they have a pivotal role in vision, photosynthesis and DNA stability . Accurate theoretical methods for examining conical intersections are at present limited to small molecules. Experimental investigations are challenged by the required time resolution and sensitivity. Current structure-dynamical understanding of conical intersections is thus limited to simple molecules with around ten atoms, on timescales of about 100 fs or longer . Spectroscopy can achieve better time resolutions , but provides indirect structural information. Here we present few-femtosecond, atomic-resolution videos of photoactive yellow protein, a 2,000-atom protein, passing through a conical intersection. These videos, extracted from experimental data by machine learning, reveal the dynamical trajectories of de-excitation via a conical intersection, yield the key parameters of the conical intersection controlling the de-excitation process and elucidate the topography of the electronic potential energy surfaces involved.