Conformational Distribution of a Multidomain Protein Measured by Single-Pair Small-Angle X-ray Scattering.

Area of Science:

• Structural Biology
• Biophysics
• Protein Dynamics

Background:

• Understanding protein conformational distribution in solution is crucial for mechanistic insights but remains challenging.
• Single-pair small-angle X-ray scattering (SAXS) offers a way to measure distance distributions, but its application to proteins is limited by technical hurdles.

Purpose of the Study:

• To adapt and apply single-pair SAXS for evaluating the conformational distribution of proteins in solution.
• To investigate the conformational landscape and ligand-induced changes of the multidomain enzyme MurD.

Main Methods:

• Development of a synthetic tag to immobilize lanthanide ions at specific protein sites.
• Application of single-pair SAXS with contrast matching to measure distance distributions.
• Analysis of the conformational distribution of the multidomain protein enzyme MurD.

Main Results:

• Successfully applied single-pair SAXS with a novel tagging strategy to a protein system.
• Revealed a broad conformational distribution for the multidomain enzyme MurD in solution.
• Demonstrated ligand-driven shifts in the conformational distribution of MurD.

Conclusions:

• The developed single-pair SAXS strategy is effective for probing protein conformational dynamics in solution.
• This method provides a powerful tool for studying dynamic proteins, including multidomain and intrinsically disordered proteins.
• The findings offer new avenues for understanding protein function through solution structural biology.