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

Area of Science:

• Molecular dynamics
• Biophysics
• Quantum chemistry

Background:

• Molecular structural dynamics are governed by potential energy landscapes.
• Conical intersections are crucial funnels connecting potential energy surfaces, vital in biological processes like vision and DNA stability.
• Current understanding of conical intersections is limited to small molecules due to experimental time resolution and sensitivity challenges.

Purpose of the Study:

• To investigate the dynamics of conical intersections in large biomolecules.
• To achieve atomic-resolution, few-femtosecond timescale observations of molecular processes.
• To elucidate the role of conical intersections in de-excitation pathways.

Main Methods:

• Utilized machine learning to extract atomic-resolution videos from experimental data.
• Applied advanced spectroscopic techniques for high time-resolution measurements.
• Focused on photoactive yellow protein, a large, 2,000-atom protein.

Main Results:

• Generated few-femtosecond, atomic-resolution videos of a large protein passing through a conical intersection.
• Revealed the dynamical trajectories of de-excitation via conical intersections.
• Determined key parameters controlling de-excitation and mapped the topography of involved electronic potential energy surfaces.

Conclusions:

• This study overcomes previous limitations in studying conical intersections for large molecules.
• Provides direct visualization of ultrafast molecular dynamics at conical intersections.
• Offers new insights into fundamental processes in photobiology and quantum chemistry.