X-ray photon correlation spectroscopy of hydrated lysozyme at elevated pressures

Area of Science:

• Biophysics
• Protein dynamics
• High-pressure science

Background:

• Pressure is a key factor influencing protein conformation and stability.
• Understanding protein behavior under pressure is crucial for various applications.

Purpose of the Study:

• To investigate the effects of elevated pressure on hydrated lysozyme proteins.
• To analyze nanoscale stress relaxation dynamics at pressures up to 0.4 GPa.

Main Methods:

• Utilized X-ray photon correlation spectroscopy (XPCS) for structural and dynamical analysis.
• Employed a diamond anvil cell (DAC) to achieve high-pressure conditions.
• Measured nanoscale stress relaxation induced by pressure.

Main Results:

• Observed a non-monotonic stress-relaxation behavior in lysozyme proteins with increasing pressure.
• A slowing down of dynamics up to 0.2 GPa was followed by re-acceleration at 0.4 GPa.
• Non-monotonic behavior in Porod and Kohlrausch-Williams-Watts (KWW) exponents indicated a crossover between 0.2 and 0.4 GPa.

Conclusions:

• Pressure-induced structural changes alter protein collective stress-relaxation.
• A transition from a jammed state to an elastically driven regime occurs under pressure.
• Findings are relevant for protein stability under compression and high-pressure technologies.