Revisiting the conundrum of trehalose stabilization

Area of Science:

• Biochemistry
• Molecular Biology
• Computational Chemistry

Background:

• Protein instability leads to aggregation and loss of function.
• Trehalose is a known cosolvent that stabilizes proteins, but its exact mechanism is debated.
• Existing theories on trehalose stabilization show discrepancies.

Purpose of the Study:

• To investigate the mechanism of trehalose's effect on protein stability.
• To analyze the influence of trehalose on native, partially unfolded, and denatured states of lysozyme.
• To resolve discrepancies in current theories regarding trehalose's stabilizing role.

Main Methods:

• Molecular dynamic (MD) simulations were employed to study lysozyme.
• Simulations were conducted under varying temperature and trehalose concentration conditions.
• Analysis included two-dimensional contour plots, principal component analysis, free energy landscape, Delphi results, and preferential interaction parameter calculations.

Main Results:

• Trehalose promotes on-pathway stabilization by slowing protein dynamics, leading to a homogeneous ensemble of native-like conformations.
• The free energy landscape showed a higher population of the native state compared to intermediate and denatured states.
• Favorable interactions between trehalose and specific polar flexible residues on the protein surface contribute to native state stabilization.

Conclusions:

• Trehalose stabilizes proteins by preferentially stabilizing the native state, rather than destabilizing the denatured state.
• The observed stabilization arises from a complex interplay of protein-trehalose, water-trehalose, water-water, protein-water, and trehalose-trehalose interactions.
• Findings challenge the common notion of relative destabilization of the denatured state by trehalose.