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Pressure-induced pKa variations influence conformations of pH-sensitive polymers
Ved Mahajan1, Varun Mandalaparthy1, Nico F A van der Vegt1
1Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany.
The Journal of Chemical Physics
|February 25, 2026
Summary
Increasing pressure unfolds polymers, but charge significantly reduces this effect. Polymers exhibit pressure-dependent pKa shifts and unique behaviors in response to combined pressure and pH changes.
Area of Science:
- Polymer science and biophysics
- Investigating macromolecular behavior under environmental stress
Background:
- Macromolecular conformations are governed by hydrophobic, electrostatic, and hydrogen-bonding interactions.
- Environmental factors like pressure and pH critically influence structural stability.
Purpose of the Study:
- To investigate the pressure response of a pH-sensitive polymer using simulations.
- To understand how pressure modulates polymer structure and charge regulation.
Main Methods:
- Constant-pH molecular dynamics simulations in explicit solvent.
- Analysis of polymer unfolding and charge behavior under varying pressure.
Main Results:
- Increasing pressure unfolds both neutral and charged polymers, with reduced unfolding in charged states.
- Observed pressure-dependent pKa shifts and enhanced unfolding at pH = pKa.
- Polyampholytes show pressure-induced salt-bridge denaturation and competition between electrostatic and hydration effects.
Conclusions:
- Charge significantly influences polymer response to pressure, highlighting coupled regulation.
- Pressure can induce pKa shifts and alter macromolecular behavior, relevant to biological systems and synthetic polymers.
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