Multiple PEG Chains Attached onto the Surface of a Helix Bundle: Conformations and Implications

We investigate the conformations of multiple poly ethylene glycol (PEG) chains conjugated to the exterior surface of a three-helix coiled coil using all-atomistic molecular dynamics simulations in an explicit solvent. Our simulations indicate that the helical content and coiled coil configuration of the peptide assembly are preserved at low degrees of polymerization. We observe that the conjugated PEG chains form a mushroomlike protective shell around the coiled coil, where the scaling of radius of gyration of PEG with molecular weight further confirms minimal steric hindering between chains. Our simulations suggest that conjugation of low-molecular weight polymers to coiled coils at densities approaching one conjugate per heptad does not induce unfolding, and in contrast may be a viable means to further improve compatibility and stability in biomaterials and drug delivery applications.