(220h) Understanding Temperature-Responsive Behavior of Elastin-like Polypeptides

The elastin-like polypeptide (ELP) is temperature sensitive biopolymer which undergoes conformational transition at critical inverse transition temperature or LCST; the feature which has led to their use in a variety of applications. ELPs are defined by a pseudo-periodic, low complexity sequence with repeat motifs, as in a model system with repeat sequence of VPGXG. Substitution of X residue with various amino acids or modifications of chain length and solute quality allows for tuning the inverse transition temperature. However, the molecular origin of LCST and the observed differences as a function of various factors are not yet completely understood. In order to elucidate the factors driving the conformational transitions of ELPs we performed large scale all-atom molecular dynamics simulations of ELPs with different sequence and length and at a range of temperatures. Comprehensive analyses of the hydrophobicity, shape, size, hydration and dynamics of ELPs suggest that the transition behavior includes the thermal disruption of water network, loss of hydration, and increase in peptide hydrophobicity. In this talk I will discuss the temperature sensitive behavior of polypeptides as a function of sequence, sequence direction, length, and concentration. The results from our study provide an atomic-level description of the thermo-responsive conformational properties of elastin-like peptides and explain experimental observations.