Vibrational spectroscopic studies of L,D-alternating valine peptides
نویسنده
چکیده
Raman and infrared spectra of Boc-(L-Val-D-Val),-OMe [(LD-Val),], with n = 4, 6 and 8, were obtained in crystalline and solution states. Based on predictions from normal-mode calculations of a number of relevant singleand double-stranded p-helix conformations, structures were assigned for the three oligopeptides under the abovementioned conditions. In the crystalline state, all three oligopeptides have a double-stranded 7 & psa6 structure. In cyclohexane and in chloroform, the t J B’s6 structure predominates for (LD-Val),. In chloroform the (m-Val), has a p4a4 structure. (r,D-Val)s in cyclohexane and in chloroform exists predominantly in a j’ J, fisa6 structure together with
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