Revisiting volume changes in pressure-induced protein unfolding

Area of Science:

• Biochemistry
• Biophysics
• Physical Chemistry

Background:

• Hydrostatic pressure is known to induce protein unfolding.
• Significant confusion exists regarding the volume changes associated with protein conformational transitions.
• Understanding these volume effects is crucial for protein science.

Purpose of the Study:

• To review and discuss volume changes during protein unfolding.
• To clarify the sign and magnitude of these volume effects.
• To explore factors influencing volume changes, such as temperature.

Main Methods:

• Literature review of studies on protein unfolding under pressure.
• Analysis of experimental data on volume changes.
• Discussion of theoretical factors contributing to volume effects.

Main Results:

• The majority of protein unfolding events under pressure result in a volume decrease.
• Evidence suggests that the volume change can become positive at elevated temperatures.
• Differences in thermal expansivity between folded and unfolded states are implicated.

Conclusions:

• Protein unfolding under hydrostatic pressure generally leads to decreased molecular volume.
• Temperature-dependent thermal expansivity can alter the sign of the volume change.
• Further research is needed to fully elucidate the complex volume effects in protein transitions.