Influence of Anomeric Configuration, Degree of Polymerization, Hydrogen Bonding, and Linearity versus Cyclicity on the Solution Conformational Entropy of Oligosaccharides

Abstract

In their various incarnations oligosaccharides have roles that are oftentimes conformationally dependent, where this dependency can be dictated by the anomeric configuration, glycosidic linkage, and/or hydrogen bonding (H-bonding) of the sugar molecules. Examples of this phenomenon are linkage- and configuration-selective aptameric binding to oligosaccharides and taste responses that appear to depend on the H-bonding-controlled shape of sugars. Differences in the behavior and use of oligosaccharides as a function of degree of polymerization are also well-known, a classic example being the case of cyclodextrins (CDs) and the different uses and properties of α-, β-, and γ-CD. Here, we have measured the solution conformational entropy of three homologous series of oligosaccharides, linear malto- and cellooligosaccharides and cyclodextrins, using high-resolution oligomeric size-exclusion chromatography (SEC), an entropically controlled separation method. We measured the change in ΔS of the malto- and cello- series as a function of degree of polymerization (DP) and compared the effects of α vs β anomeric configuration at each DP. By comparing select maltooligosaccharides with CDs, we also measured the effect of linearity vs cyclicity on ΔS. Additionally, by performing all of these studies under both hydrogen-bond-accepting and non-hydrogen-bond-accepting conditions, we were able to isolate the effects of H-bonding on the ΔS of the malto- and cellooligosaccharides and cyclodextrins as well.

Conformational properties of glucose-based disaccharides investigated using molecular dynamics simulations with local elevation umbrella sampling

“…These results are qualitatively in line with the results of a chromatographic study comparing estimated conformational entropies for T bb , M, C, I, and G in aqueous solution, 227-229 which suggested a ranking G > T bb > I > C, M along with 227,228 C > M (see also 230 ) or 229 M > C in terms of decreasing entropy (the present results show an inversion between T bb and I in this series; the experimental data for C and M differ in the quoted studies).…”

Relation between the Δ2 effect and the solution conformational entropy of aldohexoses and select methyl glycosides

“…(At this point, it should be noted that minor differences between some ÀDS values given in this paper and the values for the same mono-or disaccharides given elsewhere (Boone et al, 2008;Boone & Striegel, 2006;Striegel, 2003a) are almost certainly due to small differences in the average pore size, as well as the pore size distribution, of the SEC columns employed in the respective studies).…”

“…These two parameters are related via via (Boone & Striegel, 2006;Boone et al, 2008;Striegel, 2003a;Striegel et al, 2009). …”

“…Our studies have quantitated the influence of anomeric configuration, glycosidic linkage, linearity versus cyclicity, and intramolecular hydrogen bonding on the flexibility of select diand oligosaccharides in aqueous and polar aprotic organic solvents (Boone, Nymeyer, & Striegel, 2008;Boone & Striegel, 2006;Striegel, 2003a). With few exceptions (Striegel, 2003a), monosaccharides have remained unexamined by this method.…”

The obstruction factor in size-exclusion chromatography. 1. The intraparticle obstruction factor

“…This conclusion was arrived at by determining the K SEC of the various PS and PMMA standards used at two different temperatures, 30 and 50 • C. With this 20 • C change in temperature, the biggest change in K SEC observed was only 2% and, in most cases, the change was <1%. Had there been a substantial enthalpic contribution to the separation, we would have expected a much larger change in K SEC (on the order of 10-20% or more) with a 20 • C change in temperature [6,25,26]. Tables 1-3 and Figs.…”