Stabilization of Zwitterionic Versus Canonical Glycine by DMSO Molecules

Area of Science:

• Computational chemistry
• Biomolecular modeling
• Solvent effects on molecular conformation

Background:

• Amino acid conformation stabilization is vital for understanding biomolecular interactions.
• Dimethyl sulfoxide (DMSO) is frequently used in protein crystallization protocols.

Purpose of the Study:

• To computationally investigate glycine's conformational stabilization by dimethyl sulfoxide (DMSO) molecules.
• To compare DMSO's effects with those of water on glycine's canonical and zwitterionic forms.

Main Methods:

• Density Functional Theory (DFT) calculations at B3LYP/6-311++G(d,p) level.
• Analysis of glycine-DMSO clusters with one and two DMSO molecules.
• Implicit solvent calculations and comparison with water clusters.

Main Results:

• One DMSO molecule stabilizes glycine's zwitterionic form through specific interactions.
• Two DMSO molecules significantly reduce the energy gap between glycine's forms.
• The zwitterionic form becomes more stable in pure DMSO below 150 K.

Conclusions:

• DMSO exhibits unique stabilizing properties for amino acid zwitterionic forms.
• Findings offer insights into DMSO's role in biomolecular stabilization.
• Results have implications for optimizing protein crystallization protocols using DMSO.