Figure 2.
(a) Hydration free energies of extended (ϕ = −139°, ψ = 135°) polyalanyl peptides having 1-4 alanyl groups, calculated with the OPLS-AA, the original PACE (PACEold) and the new PACE (PACEnew) force fields. The error bars are estimated with three independent simulations. (b) Potential mean force (PMF) profiles of two interacting amides in water, calculated with the OPLS-AA force field (thin line), the new PACE (thick line), the original PACE (dashed line) and the original HB potentials with the new hydration parameters (dot-dashed line).