Multidomain structure and correlated dynamics determined by self-consistent FRET networks

Area of Science:

• Biochemistry
• Structural Biology
• Biophysics

Background:

• Understanding protein structure-dynamics is crucial for biological function.
• Multidomain proteins exhibit complex conformational flexibility.
• Existing methods often struggle to capture both structure and dynamics simultaneously in solution.

Purpose of the Study:

• To develop and validate a hybrid approach for simultaneous structure and dynamics analysis of multidomain proteins.
• To investigate the conformational landscape and dynamics of the heat shock protein 90 (Hsp90).
• To characterize the impact of protein-protein interactions on protein dynamics.

Main Methods:

• Combining self-consistent networks of distance distributions with known domain structures.
• Analyzing time-resolved single-molecule fluorescence parameters to correlate local and global dynamics.
• Applying the method to the multidomain protein Hsp90 in solution.

Main Results:

• The average solution structure of Hsp90's closed state matches X-ray crystal structures with Angstrom precision.
• Hsp90's open state comprises an ensemble of conformations with significant interdomain fluctuations (up to 25 Å).
• Dynamic protein-protein interactions were found to suppress submillisecond fluctuations in a state-specific manner.

Conclusions:

• The developed hybrid approach successfully provides simultaneous access to structure and dynamics of multidomain proteins.
• Hsp90 exhibits substantial conformational flexibility, influenced by protein-protein interactions.
• The method allows for the localization and functional characterization of dynamic elements and domain interfaces in proteins.