Fig. 2.

The pair correlation functions g_HB–OU(r) (gray) and g_HB–OW(r) (black) probe the formation of HBs between backbone amides and urea or water molecules, respectively. Data are collected over 40,000 conformational snapshots of Aβ_16–22 monomers from four 10-ns trajectories in 8 M OPLS urea solution. There is a dramatic preference for backbone amides to form HBs with urea molecules. (Inset) The functions g_HB–OW(r) obtained for aqueous urea (gray) and water (black). Similarity between g_HB–OW(r) plots suggests that urea causes minimal perturbation in local water structure.