[NMR paper] Interresidual hydrogen bonding in carbohydrates unraveled by NMR spectroscopy and molecular dynamics simulations.

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Interresidual hydrogen bonding in carbohydrates unraveled by NMR spectroscopy and molecular dynamics simulations.

Related Articles Interresidual hydrogen bonding in carbohydrates unraveled by NMR spectroscopy and molecular dynamics simulations.

Chembiochem. 2019 May 08;:

Authors: Rönnols J, Engström O, Schnupf U, Säwén E, Brady JW, Widmalm G

Abstract
Carbohydrates, also known as glycans in biological systems, are omnipresent in nature where they as glycoconjugates occur as oligo- and polysaccharides linked to lipids and proteins. Their three-dimensional structure is defined by two or three torsion angles at each glycosidic linkage. In addition, transglycosidic hydrogen bonding between sugar residues may be important. Herein we investigate the presence of these interresidue interactions by NMR spectroscopy in D2O:DMSO-d6 (70:30) or D2O and by molecular dynamics (MD) simulations with explicit water as solvent for disaccharides with structural elements ?-d-Manp-(1->2)-d-Manp, ?-d-GlcpNAc-(1->2)-d-Manp, and ?-d-Glcp-(1->4)-?-d-Glcp, all of which have been suggested to exhibit interresidue hydrogen bonding. For the disaccharide ?-d-GlcpNAc-(1->2)-?-d-Manp-OMe the large extent of O5'···HO3 hydrogen bonding as seen from the MD simulation is implicitly supported by 1H NMR chemical shift and 3JHO3,H3 value of the hydroxyl proton. In the case of ?-d-Glcp-(1->4)-?-d-Glcp-OMe existence of a transglycosidic hydrogen bond O2'···HO3 was proven by the presence of a cross-peak in 1H,13C-HSQC-TOCSY experiments as a result of direct TOCSY transfer between HO3 of the reducing end residue and H2' (detected at C2') of the terminal residue. The occurrence of interresidue hydrogen bonding, albeit transient, is judged important for stabilization of three-dimensional structures.


PMID: 31066963 [PubMed - as supplied by publisher]



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