CONFORMATIONAL CHARACTERISTICS OF THE N‐ACETYL‐N‘‐METHYLAMIDES OF THE FOUR (LYS, TYR) DIPEPTIDES

Abstract

The conformational properties of the N‐acetyl‐N'‐methylamides of the dipeptides lysyl‐lysine, lysyl‐tyrosine, tyrosyl‐lysine, and tyrosyl‐tyrosine were studied by means of conformational energy calculations, by n.m.r. measurements in deuterated dimethylsulfoxide, and by circular dichroism in water, methanol, dioxane‐water, and trifluoroethanol. Since these four dipeptides occur occasionally as bends in proteins, it was of interest to see whether short‐range interactions, acting within the terminally blocked dipeptides, are sufficient to stabilize bend conformations significantly over other conformations. It was found that the four dipeptides exist as ensembles of conformations in solution. T..