Elastic properties of poly(ethylene-glycol) studied by molecular dynamics stretching simulations

Unfolding and elastic properties of single poly(ethylene-glycol) (PEG) poly mers were studied by molecular dynamics (MD) simulations. The simulations w ere performed in close resemblance to recent single molecule force spectros copy experiments, and thus allowed an interpretation of these experiments a t the atomic level. In agreement with these experiments, the water solvent was found to drastically affect the elastic properties of PEG. Our simulati ons explain this effect in terms of local helical structures which are stab ilized through water bridges. Stretching forces of more than 100 pN were re quired to break these water bridges and thereby to destroy these helical st ructures. (C) 1999 Elsevier Science B.V. All rights reserved.