Highly fluctuating protein structures revealed by variable-pressure nuclear magnetic resonance

Area of Science:

• Biochemistry and structural biology
• Protein dynamics and conformational analysis

Background:

• Basic protein folded structures are well-understood.
• Knowledge of higher-energy protein conformers is limited, hindering understanding of protein function, folding, and diseases.

Purpose of the Study:

• To develop and apply a novel experimental strategy to detect and analyze higher-energy protein conformers.
• To investigate the structural and functional significance of these rare conformers under physiological conditions.

Main Methods:

• Utilized pressure perturbation combined with multidimensional Nuclear Magnetic Resonance (NMR) spectroscopy.
• Applied the technique to various proteins including RalGDS, beta-lactoglobulin, and ubiquitin.

Main Results:

• Successfully detected and characterized a range of rare conformers under pressure for multiple proteins.
• Observed protein structures existing between fully folded and unfolded states.
• Identified conformers resembling kinetic intermediates, suggesting functional roles.

Conclusions:

• Variable-pressure NMR is effective for studying transient and low-population protein conformers.
• Higher-energy conformers represent a significant, functionally relevant part of the protein conformational landscape.
• This approach expands the understanding of protein structure, dynamics, and disease mechanisms.