Solution conformation of chitobiose. Evidences for the existence of conformational averaging around the glycosidic linkages from NMR spectroscopy experiments and molecular mechanics calculations

The solution conformation of N, N-diacetyl-D-chitobiose (GlcNAc beta-(1 --> 4) GlcNAc) (1) has been studied by NMR relaxation measurements (ID-NOE, NOESY, ROESY) and molecular mechanics calculations with the MM3* and AMBER/Homans force fields. The results presented here indicate the existence of important flexibility around the glycosidic linkage. with the presence of at least two different conformations, in contrast with previous reports which presented chitobiose basically as a monoconformational entity.