Structure of aqueous sodium perchlorate solutions

Area of Science:

• Physical Chemistry
• Biophysics
• Computational Chemistry

Background:

• The Hofmeister series describes how different salts affect protein solubility and folding.
• Protein folding is a critical process with significant implications in biology and medicine.
• Understanding salt effects on protein structure is essential for controlling solubility and stability.

Purpose of the Study:

• To characterize the effects of sodium perchlorate on aqueous solutions.
• To investigate the influence of salt concentration on water organization and hydrogen bonding.
• To determine how sodium perchlorate affects the stability of a folded peptide.

Main Methods:

• Molecular dynamics simulations at room temperature.
• Analysis of radial distribution functions for solvent and cosolvent organization.
• Study of hydrogen bond networks within solvation shells.
• Application of Kirkwood-Buff theory to calculate activity coefficients.

Main Results:

• Sodium perchlorate alters water organization beyond the first solvation shell, impacting the second hydration shell.
• Hydrogen bond analysis reveals changes in water-ion interactions within solvation shells.
• Increased sodium perchlorate concentration enhances the stability of a folded AP peptide helix.

Conclusions:

• Salt effects extend beyond the immediate solvation shell, influencing water structure more broadly.
• Sodium perchlorate acts as a stabilizing agent for peptide structures in aqueous solutions.
• The study provides insights into the molecular mechanisms of salt-induced protein stabilization.