Synthesis and structural investigation of a series of mannose-containing oligosaccharides using mass spectrometry

Abstract

A series of compounds associated with naturally occurring and biologically relevant glycans consisting of α-mannosides were prepared and analyzed using collision-induced dissociation (CID), energy-resolved mass spectrometry (ERMS), and H nuclear magnetic resonance spectroscopy. The CID experiments of sodiated species of disaccharides and ERMS experiments revealed that the order of stability of mannosyl linkages was as follows: 6-linked> 4-linked ≧ 2-linked > 3-linked mannosyl residues. Analysis of linear trisaccharides revealed that the order observed in disaccharides could be applied to higher glycans. A branched trisaccharide showed a distinct dissociation pattern with two constituting disaccharide ions. The estimation of the content of this ion mixture was possible using the disaccharide spectra. The hydrolysis of mannose linkages at 3- and 6-positions in the branched trisaccharide revealed that the 3-linkage was cleaved twice as fast as the 6-linkage. It was observed that the solution-phase hydrolysis and gas-phase dissociation have similar energetics.

Glycosidic α-linked mannopyranose disaccharides: an NMR spectroscopy and molecular dynamics simulation study employing additive and Drude polarizable force fields

“…40,41 Standard workup, silica-based purification, and deprotection via a two-step procedure using (i) NaOMe in MeOH and (ii) triethylsilane and Pd/C in MeOH 42 yielded the deprotected disaccharide α- d -[1,2- 13 C 2 ]Man p -(1→4)-α- d -Man p -OMe, which was purified by gel-permeation chromatography. 1 H and 13 C NMR chemical shift data in agreement with those previously reported; 34 1 J C1′,C2′ = 47.4 Hz. HR-ESI-MS: m/z calc.…”

“…Disaccharides available from previous studies were α- d -Man p -(1→2)-α- d -Man p -OMe ( M2M ) and α- d -Man p -(1→3)-α- d -Man p -OMe ( M3M ), 36 α- d -Man p -(1→4)-α- d -Man p -OMe ( M4M ), 34 α- d -Man p -(1→6)-α- d -Man p -OMe ( M6M ) and α- d -Man p -(1→6)-α- d -[6- 13 C]Man p -OMe ( M6M- c ). 37…”

“…71 Like for the φ/ψ maps describing the conformational space at the glycosidic linkage of the mannobioses a broader population distribution is exhibited at ω torsions for the Drude force field compared to the classical CHARMM36 force field for the studied disaccharides (Figure 7 and Figures S1 -S3). a 297 K from Daikoku et al 34 with H5ꞌ,H6ꞌpro-R = 5.7 Hz, H5ꞌ,H6ꞌpro-S = 2.1 Hz, H5,H6pro-R = 5.8 Hz and H5,H6pro-S = 2.1 Hz; b (in parenthesis) 343 K from Rönnols et al 113 with H5ꞌ,H6ꞌpro-R = 5.57, H5ꞌ,H6ꞌpro-S = 2.24 Hz, H5,H6pro-R = 5.72 Hz and H5,H6pro-S = 2.29 Hz; c 310 K from Olsson et al 37 with H5,H6pro-R = 5.12 Hz and H5,H6pro-S = 1.96 Hz.…”

Primary Structure of Glycans by NMR Spectroscopy

“…The hydrolysis is typically carried out at an elevated temperature of ∼ 95 °C, but the duration depends to a great deal on the ease of release of the monosaccharides from the native material, as well as on the changes that may occur to the sugar residues during the strong acidic conditions, which for some sugars lead to formation of 1,6-anhydro derivatives, degradation, or complete decomposition. The optimum reaction conditions can be investigated through a time-course monitoring of the hydrolysis process directly in the NMR tube …”

“…The optimum reaction conditions can be investigated through a time-course monitoring of the hydrolysis process directly in the NMR tube. 186 Frequently, the identity of the monosaccharides residues can directly be assessed by analysis of NMR spectroscopic data of each monosaccharide spin system in the native oligo-or polysaccharide (vide infra section 4.3). In the case of bacterial polysaccharides, this kind of analysis is facilitated when biosynthetic information is available prior to the NMR analysis.…”