Crystal Structure of Nystose Trihydrate

Abstract

Abstract A tetrasaccharide, O-α-d-glucopyranosyl-(1→2)-O-β-d-fructofuranosyl-(1→2)-O-β-d-fructofuranosyl-(1→2)-O-β-d-fructofuranoside (nystose) trihydrate (C24H42O21·3H2O), was crystallized from its aqueous solution by using seed crystals. The crystal structure has been determined by an X-ray diffraction method. The crystal data are as follows: orthorhombic, P212121, Z = 4, a = 13.582(3), b = 23.385(6), and c = 10.198(2) Å. The α-d-glucopyranose ring has the normal type 4C1 chair conformation, and three fructofuranose rings have the 4T3, E4, and 4T3 (or E3) conformations. As in the 1-kestose crystal, all of the hydrogen bonds found made connections between adjacent molecules. Although the linkage conformation (∠C1O1C1–2C1–1, ∠C2C1O1C1–2) of the sucrose component in nystose (100.3°, −137.1°) was different from that in 1-kestose (53.3°, −152.9°), the linkage conformation (φ,ψ,ω) of the inulobiose component at the end of nystose (71.3°, −165.9°, 68.0°) was very similar to that of 1-kestose (80.5°, −169.6°, 56.5°).