Hydration study of homopolypeptides by 2 H NMR

Deuteron T 1 and T 2 was studied as a function of hydration in homopolyglycine (PG) and homopolyproline (PP). Water deuteron relaxation rates in PG conform to a hydration model involving two types of primary hydration sites where water is directly bonded to the polymer. Once these sites are filled, additional water only bonds to water molecules at the primary sites and in so doing affect their dynamics. PP exhibits an anomalous T 1 and T 2 hydration dependence which has been interpreted in terms of a cooperative water molecule–PP molecule helical conformational rearrangement which occurs once a certain hydration level is reached. The proposal of a water–PP structure is tested using molecular dynamics simulations. © 2007 Wiley Periodicals, Inc. Biopolymers 86: 11–22, 2007. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com