Insights into Protein Unfolding under pH, Temperature, and Shear using Molecular Dynamics Simulations

Abstract: Protein biologics hold immense potential in therapeutic applications, but their ephemeral nature has hindered their widespread application. The effects of different stressors on protein folding have long been studied, but whether these stressors induce protein unfolding through different pathways remains unclear. In this work, we conduct all-atom molecular dynamics simulations to investigate the unfolding of bovine serum albumin (BSA) under three distinct external stressors: high temperature, acidic pH, and shear stress. Our findings reveal that each stressor induces unique unfolding patterns in BSA, indicating stressor-specific unfolding pathways. Detailed structural analysis showed that high temperature significantly disrupts the protein's secondary structure, while acidic pH causes notable alterations in the tertiary structure, leading to domain separation and an extended shape. Shear stress initially perturbs the tertiary structure, initiating structural rearrangements followed by a loss of secondary structure. These distinct unfolding behaviors suggest that different stabilization strategies are required to enhance protein stability under various denaturation conditions. Insights from these unfolding studies can inform the design of materials, especially polymers, aimed at improving protein stability.