Agreement Between Experimental and Simulated Circular Dichroic Spectra of a Positively Charged Peptide in Aqueous Solution and on Self-Assembled Monolayers

Successfully immobilizing functional proteins on inorganic surfaces has long been a challenge to the biophysics and bioengineering communities. This is due, in part, to a lack of understanding of the effect of nonaqueous environments on protein structure from both experimental and computational perspectives. Because most experimental information about protein structure comes from the Protein Data Bank and is collected from an aqueous solvent environment, modern force fields for molecular dynamics (MD) simulations are parameterized against these data. The applicability of such force fields to biomolecules in different environments, including when in contact with surfaces and substrates, must be validated. Here, we present MD folding simulations of a highly charged peptide solvated in water, solvated in a solution of 2:1 t-BuOH/H2O and bound to the surface of a methyl-terminated self-assembled monolayer (SAM), and compare the structures predicted by these simulations to previously reported circular dichrois...