Structure cristalline du mélézitose monohydraté

Abstract

The crystal structure of the non-reducing trisaccharide melezitose monohydrate, O-e-D-glucopyranosyl-(1-->-2)-O-fl-o-fructofuranosyl-(3-->-1)-e-D-glucopyranoside, has been determined by direct methods and refined by least-squares calculations to a final R of 0.032. The space group is P212121 with four formula units of CtsHa2Ox6. H20 per unit cell. The lattice parameters are a= 14.950 (8), b= 13-863 (6), c= 10.812 (4) ,~. The e-o-glucopyranoside units are in the Cx chair conformation with the same conformation (gg) around the Cs-C6 extracyclic bond. The fructofuranoside unit adopts the twist conformation 4Ta. The conformation of the 1 -+ 2 linkage in the sucrose moiety is compared with those of planteose, raffinose, L-kestose and sucrose. Molecules are associated in the crystal by an extensive network of hydrogen bonds: one bifurcated intramolecular hydrogen bond is found; the three ring oxygen atoms accept a hydrogen bond; the majority of the hydroxyl groups are both donor and acceptor.

Structure of 6-kestose monohydrate, C18H31O16.H2O

“…Bond distances and angles. C-C bond distances do not differ significantly in the three rings [1.524 (7,4) Avenel, Neuman & Gillier-Pandraud (1976) as an average over 23 glucosyl residues. The average C-O distance of the C-O-C bridges [1.422 (3,4)A] is not very different from that value.…”

“…The reciprocal position of the two GP and FF tings can be defined by means of the two torsion angles ¢=O(5)-C(1)-O(1)-C'(2) and ~,= O'(2)-C'(2)-O(1)-C(1) and it is found that the total variation range in the six sugars is 25.9 ° for q~ and 77.2 ° for ~' (see Avenel et al, 1976).…”

“…The glucopyranosyl-(1--,2)-O-fl-o-fructofuranosyl linkage occurs in sucrose (Brown & Levy, 1973) and in the sucrose units of raffinose (Berman, 1970), 1-kestose (Jeffrey & Park, 1972), melezitose (Avenel et al, 1976), planteose (Rohrer, 1972) and 6-kestose. The reciprocal position of the two GP and FF tings can be defined by means of the two torsion angles ¢=O(5)-C(1)-O(1)-C'(2) and ~,= O'(2)-C'(2)-O(1)-C(1) and it is found that the total variation range in the six sugars is 25.9 ° for q~ and 77.2 ° for ~' (see Avenel et al, 1976).…”

Sucrose analogs: an attractive (bio)source for glycodiversification

“…Melezitose has been crystallized in two monohydrated forms. [54][55][56] Gentianose (b-D-glucopyranosyl-(1-6)-a-D-glucopyranosyl-(1-2)-b-D-fructofuranoside) is another glucosyl derivative of sucrose trisaccharide that was first extracted from Gentiana lutea 57 and is commonly found in gentian roots, hence its name.…”

Etude structurale par diffraction des rayons X d'un dianhydride glycofurannique: bis(O-acétyl-3 désoxy-5α-D-xylofurannose) dianhydride-1,2':2,1'

“…Des r6sultats parall61es se retrouvent dans un d+rivb de l'acide L-iduronique (Klaska, Jarchow, Gi.inther & Paulsen, 1978), dans l'anhydro-2,6 fl-D-fructofurannose (Dreissig & Luger, 1973) et dans le fl-D-mannofurannose-CaCl2.4H20 (Craig, Stephenson & Stevens, 1972). Par contre, la plupart des cycles furanniques adoptent la conformation 'twist' (Avenel et al, 1976). Pour les deux molecules, les angles entre les plans moyens du cycle hexagonal et des cycles pentagonaux prennent une valeur moyenne de 49,7 ° (valeurs extremes 49,0 et 50,1°).…”