Crystal structure of methyl α-l-rhamno-pyranosyl-(1→2)-α-l-rhamno-pyran-oside monohydrate.

ABSTRACT: The title compound, C₁₃H₂₄O₉·H₂O, a structural model for part of bacterial O-anti-gen polysaccharides from Shigella flexneri and Escherichia coli, crystallizes with four independent disaccharide mol-ecules and four water mol-ecules in the asymmetric unit. The conformation at the glycosidic linkage joining the two rhamnosyl residues is described by the torsion angles φ_H of 39, 30, 37 and 37°, and ψ_H of -32, -35, -31 and -32°, which are the major conformation region known to be populated in an aqueous solution. The hexo-pyran-ose rings have the ¹ C ₄ chair conformation. In the crystal, the disaccharide and water mol-ecules are associated through O-H⋯O hydrogen bonds, forming a layer parallel to the bc plane. The layers stack along the a axis via hydro-phobic inter-actions between the methyl groups.

SUBMITTER: Eriksson L 

PROVIDER: S-EPMC6658941 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature