Pressure-induced changes in the folded structure of lysozyme

Area of Science:

• Biophysics
• Structural Biology
• Protein Dynamics

Background:

• Proteins undergo conformational changes crucial for their function.
• Understanding how external factors like pressure affect protein structure is vital.
• Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for studying biomolecules in solution.

Purpose of the Study:

• To investigate pressure-induced structural alterations in proteins in solution.
• To demonstrate a novel method for observing these changes using high-resolution NMR.
• To characterize the effect of pressure on the hydrophobic core of lysozyme.

Main Methods:

• Utilized a custom-built, continuously variable pressure cell integrated with a 750 MHz NMR spectrometer.
• Monitored pressure-induced diamagnetic chemical shifts of over 26 protons in lysozyme.
• Applied hydrostatic pressure ranging from 1 to 2000 bar.

Main Results:

• Observed significant pressure-induced changes in the overall folded structure of lysozyme in solution.
• Identified protein compaction, particularly within the hydrophobic core, as the primary response to pressure.
• Successfully tracked chemical shift perturbations across multiple protein residues.

Conclusions:

• Pressure can induce substantial structural rearrangements in proteins within their solution state.
• The developed NMR technique offers a versatile approach to probe protein internal flexibility under varying pressure conditions.
• The findings highlight the role of hydrophobic interactions in protein response to hydrostatic pressure.