Conformational Analysis of -Glycosidic Linkages in 13C-Labeled Glucobiosides Using Inter-residue Scalar Coupling Constants
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- 作者：Ulrika Olsson ; Anthony S. Serianni ; Roland Stenutz
- 刊名：Journal of Physical Chemistry B
- 出版年：2008
- 出版时间：April 10, 2008
- 年：2008
- 卷：112
- 期：14
- 页码：4447 - 4453
- 全文大小：103K
- 年卷期：v.112,no.14(April 10, 2008)
- ISSN：1520-5207
文摘
Four 
-linked glucobioses selectively 13C labeled at C1' or C2' have been prepared. The inter-residue couplingconstants, JCH, and JCC, have been determined and related to the solution conformations of the disaccharidesusing Karplus-type relationships. Relying only on the experimental coupling constants, glycosidic linkageconformation in methyl 
-sophoroside (methyl 2-O--D-glucopyranosyl--D-glucopyranoside), methyl -laminarabioside (methyl 3-O--D-glucopyranosyl--D-glucopyranoside), and methyl -cellobioside (methyl 4-O--D-glucopyranosyl--D-glucopyranoside) were found to be close to those observed in the solid state (39
<
H < 41, -24 < 
H < -36). The laminarabioside and cellobioside were found to have conformationsthat accommodate an intramolecular hydrogen bond to O5' that is observed in the solid state. In all compounds,the exocyclic hydroxymethyl groups retain a conformation close to that observed in unsubstituted glucose(gt/gg 1:1). Methyl -gentiobioside (methyl 6-O--D-glucopyranosyl--D-glucopyranoside) shows greaterflexibility at the -torsion than the other disaccharides, but the population distribution around the C5-C6bond is essentially unaffected by substitution. None of the O2' hydroxyl groups of the -D-glucopyranosylresidues in any of the disaccharides appear to be involved in inter-residue hydrogen bonding since 1JCH, 1JCC,and 2JCH values sensitive to C2'-O2' rotamer distribution remain close to those observed in methyl -D-glucopyranoside.
-linked glucobioses selectively 13C labeled at C1' or C2' have been prepared. The inter-residue couplingconstants, JCH, and JCC, have been determined and related to the solution conformations of the disaccharidesusing Karplus-type relationships. Relying only on the experimental coupling constants, glycosidic linkageconformation in methyl -sophoroside (methyl 2-O--D-glucopyranosyl--D-glucopyranoside), methyl -laminarabioside (methyl 3-O--D-glucopyranosyl--D-glucopyranoside), and methyl -cellobioside (methyl 4-O--D-glucopyranosyl--D-glucopyranoside) were found to be close to those observed in the solid state (39 <H < 41, -24 < H < -36). The laminarabioside and cellobioside were found to have conformationsthat accommodate an intramolecular hydrogen bond to O5' that is observed in the solid state. In all compounds,the exocyclic hydroxymethyl groups retain a conformation close to that observed in unsubstituted glucose(gt/gg 1:1). Methyl -gentiobioside (methyl 6-O--D-glucopyranosyl--D-glucopyranoside) shows greaterflexibility at the -torsion than the other disaccharides, but the population distribution around the C5-C6bond is essentially unaffected by substitution. None of the O2' hydroxyl groups of the -D-glucopyranosylresidues in any of the disaccharides appear to be involved in inter-residue hydrogen bonding since 1JCH, 1JCC,and 2JCH values sensitive to C2'-O2' rotamer distribution remain close to those observed in methyl -D-glucopyranoside.