Conformational studies of the β(1→3) linked disaccharide component of the immunologically active pentasaccharide of the Forssman antigen

Abstract

AbstractConformational energy calculations at the PCILO level of approximation were performed on β(1 → 3) linked disaccharide consisting of N‐acetylgalactosamine and galactose of the Forssman antigen to examine the side group conformations and their influence on the mutual orientations of the two pyranosyl rings. Two low energy regions for the glycosidic bond conformation have been located in the grid search using classical potential functions. The PCILO energy minimizations were then carried out in each of these regions. The preferred orientations of the nonreducing pyranosyl ring relative to the reducing ring were found to be in agreement with the available x‐ray results. Moreover, the orientations of groups attached to the anomeric carbons were in good accordance with the requirements of the exo‐anomeric effect.