Entropic Force in Drosophila Resilin: Molecular Dynamics Study.

Resilin is a rubber-like elastomeric protein found in many insects, including D. melanogaster (fruit fly). Resilin is highly extensible and appears to have the highest resilience among all known elastic materials. We have performed molecular dynamics study of two repeat units from the N-terminal elastomeric domain in fruit fly resilin. A single repeat unit (sequence NGGRPSSSYGAPGGG) was derived as a consensus repeat from different fruit fly species. Our simulations show high flexibility of the peptide in water and yield secondary structure content that is consistent with a disordered ensemble supported by circular dichroism (CD) spectra. In agreement with previous studies, indicating the entropic origin of the elastomeric force in resilin, we find that configurational entropy is markedly decreased upon stretching of the simulated peptide.