Control of anomericity and glycosidic linkage on the mechanics of polysaccharides.

Mechanics of polysaccharides, the most diverse class of biomolecules, is explored in this work for a variety of strands bearing α- or β-D-glucopyranose residues and linked by different glycosidic linkages. The purpose is to understand how far the glycosidic linkage type and anomericity of the monomers influence the elasticity of the polysaccharides. We have used steered molecular dynamics (SMD) simulations to understand the mechanical strain under a pulling stress. The force-extension (F-E) curves thus generated are compared to the results of atomic force microscopy (AFM) for validation. In line with expectations, our SMD results indicate that in general, the α D-glucopyranosides show conformational switching from the most stable ⁴C1 chair to a half-chair or envelope and even to a skew-boat or boat form in some cases. The β-series, however, show minimal distortion, except β D-1-2 polysaccharide, which shows some transition. The exceptional cases of 1-6 linked polysaccharides and their extra elasticity owing to the presence of an additional –CH2 group in the glycosidic linkage are also evident. In general, amongst all the polysaccharides studied, α D-1-6 glucopyranoside shows a maximum elasticity of ~ 37% per ring when exposed to a pulling stress of ~ 2100 pN. Density functional theory (DFT) calculations help estimate the single point energies of the conformers as the polysaccharide stretches in the SMD simulations. A comparative understanding of polysaccharide mechanics, as obtained from this work, would set the platform for modeling and simulation of innovative polysaccharide-based membranes down the line. [ABSTRACT FROM AUTHOR]

Steered molecular dynamics simulation of polysaccharides having α/β D-glucopyranose units linked by 1-2/1-3/1-4/1-6 types of glycosidic linkages sheds light on their mechanical properties. Down the line, the aim is to model improved polysaccharide-based membranes with tunable mechanical properties. [ABSTRACT FROM AUTHOR]

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