Structural and Dynamical Properties of Elastin-Like Peptides near their Lower Critical Solution Temperature
Elastin-like peptides (ELPs) are artificially derived intrinsically disordered proteins (IDPs) mimicking the hydrophobic repeat unit in the protein elastin. ELPs are characterized by a lower critical solution temperature (LCST) in aqueous media. Here, we investigate the sequence GVG(VPGVG)3 over a wide range of temperatures (below, around, and above the LCST) and peptide concentrations employing all-atom molecular dynamics simulations, where we focus on the role of intra- and inter-peptide interactions. We begin by investigating the structural properties of a single peptide that demonstrates a hydrophobic collapse with temperature, albeit moderate, as the sequence length is short. We observe a change in the interaction between two peptides from repulsive to attractive with temperature by evaluating the potential of mean force, indicating an LCST-like behaviour. Next, we explore dynamical and structural properties of peptides in multi-chain systems. We report the formation of dynamical aggregates with coil-like conformation, in which Val central residues play an important role. Moreover, the lifetime of contacts between chains strongly depends on the temperature and can be described by a power-law decay that is consistent with the LCST-like behaviour. Finally, the peptide translational and internal motion are slowed down by an increase in the peptide concentration and temperature.