title: Methyl 4-O-beta-L-galactopyranosyl-beta-D-glucopyranoside (methyl beta-L-lactoside).
abstract: Methyl beta-L-lactoside, C13H24O11, (II), is described by glycosidic torsion angles phi (O5Gal-C1Gal-O4Glc-C4Glc) and psi (C1Gal-O1Gal-C4Glc-C5Glc) of 93.89 (13) and -127.43 (13) degrees , respectively, where the ring atom numbering conforms to the convention in which C1 is the anomeric C atom and C6 is the exocyclic hydroxymethyl (CH2OH) C atom in both residues (Gal is galactose and Glc is glucose). Substitution of L-Gal for D-Gal in the biologically relevant disaccharide, methyl beta-lactoside [Stenutz, Shang & Serianni (1999). Acta Cryst. C55, 1719-1721], (I), significantly alters the glycosidic linkage interface. In the crystal structure of (I), one inter-residue (intramolecular) hydrogen bond is observed between atoms H3OGlc and O5Gal. In contrast, in the crystal structure of (II), inter-residue hydrogen bonds are observed between atoms H6OGlc and O5Gal, H6OGlc and O6Gal, and H3OGlc and O2Gal, with H6OGlc serving as a donor with two intramolecular acceptors.
authors.affiliation: Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, IN 46556, USA.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Pan
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Noll
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Serianni
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D003461:Crystallography; D006860:Hydrogen Bonding; D008759:Methylglycosides / Q000737:chemistry*; D008958:Models, Molecular
chemical_list: D008759:Methylglycosides; C034207:methyl lactoside