Time-resolved structural studies with serial crystallography: A new light on retinal proteins.

Area of Science:

• Structural biology
• Biophysics
• Biochemistry

Background:

• X-ray cryo-crystallography and cryo-electron microscopy have provided static structures of membrane proteins like bacteriorhodopsin and rhodopsin.
• These methods are limited in capturing transient intermediate conformational states.
• Understanding protein dynamics is crucial for elucidating biological function.

Purpose of the Study:

• To describe strategies for time-resolved structural dynamic studies of retinal proteins at room temperature.
• To explore the application of serial femtosecond crystallography (SFX) using X-ray Free Electron Lasers (X-FELs).
• To investigate the potential of X-FELs for observing conformational changes in membrane proteins within a near-physiological lipid bilayer environment.

Main Methods:

• Utilizing injector or fixed-target based serial femtosecond crystallography (SFX) at X-FELs.
• Employing pump-probe experiments to trigger and capture protein dynamics.
• Leveraging advancements in sample delivery methods for SFX at both X-FELs and synchrotron X-ray sources.

Main Results:

• Demonstrated the potential of X-FELs for tracking light-triggered protein dynamics via SFX.
• Showcased opportunities for protein 2D-crystal diffraction at X-FELs to study membrane protein conformational changes.
• Highlighted the feasibility of SFX at synchrotron sources due to improved sample delivery.

Conclusions:

• Serial femtosecond crystallography at X-FELs offers a powerful approach for studying membrane protein dynamics at room temperature.
• These time-resolved structural methods provide new insights into the conformational landscapes of light-sensitive proteins.
• Advancements in serial crystallography expand the possibilities for determining protein structures in action.