Hydrophobic Homopolymer's Coil-Globule Transition and Adsorption onto a Hydrophobic Surface under Different Conditions

Unstructuredproteins can modulate cellular responsesto environmental conditions by undergoing coil-globule transitionsand phase separation. However, the molecular mechanisms of these phenomenastill need to be fully understood. Here, we use Monte Carlo calculationsof a coarse-grained model incorporating water's effects onthe system's free energy. Following previous studies, we modeledan unstructured protein as a polymer chain. Because we are interestedin investigating how it responds to thermodynamic changes near a hydrophobicsurface under different conditions, we chose an entirely hydrophobicsequence to maximize the interaction with the interface. We show thata slit pore confinement without top-down symmetry enhances the unfoldingand adsorption of the chain in both random coil and globular states.Moreover, we demonstrate that the hydration water modulates this behaviordepending on the thermodynamic parameters. Our findings provide insightsinto how homopolymers and possibly unstructured proteins can senseand adjust to external stimuli such as nanointerfaces or stresses.