Behavior of Protein-Inspired Synthetic Random Heteropolymers

Random heteropolymers (RHPs) are an interesting class of materials useful in many theories and applications. While previous studies typically focused on simplified RHP systems, here we explore a more complex scenario inspired by highly heterogeneous molecules like proteins. Our system consists of four monomers mimicking different classes of amino acids. Using Molecular Dynamics simulations and Small-Angle X-Ray Scattering, we explore dynamical and structural features of these RHPs in solution. Our results show the RHPs assemble with heterogeneous interfaces reminiscent of protein surfaces. The polymer backbones appear frozen at room temperature on the nano- to micro-second timescale with molten globule morphology, albeit their conformational space has multiple metastable conformations for a given sequence, drawing comparison to Intrinsically Disordered Proteins. Local connectivity and chemistry are also shown to have substantial impact on polymer solvation. The work presented here indicates that RHPs share similarities with proteins to be leveraged in bio-mimetic and bio-inspired applications.