Biological activities of levan-based polymers: In silico approach

Oligo- and polysaccharides play an important role in various biological mechanisms such as immune response, adhesion and signal transduction by covering the surface of most cells. Hence considerable research has been directed on elucidating the biological activity mechanism of these polysaccharides by structure-function analysis. Use of different in vivo and in vitro bioactivity assays in such studies prevents to make generalizations in relating the chemical structure and conformation to the observed biological activity. Moreover, diversity of their conformations and their structural heterogeneity make polysaccharides the most challenging type of biopolymer for experimental and theoretical characterization studies. Levan is a naturally occurring polymer which is composed of β-D-fructofuranose with β (2→6) linkages between fructose rings. It is a homopolysaccharide that has great potential to be used as a functional biopolymer in foods, feeds, cosmetics, and pharmaceutical and chemical industries. Limited success of current technologies in analyzing the 3D structure of polysaccharides promoted the use of computational methods in structure-function studies. The main objective of this work is to study the conformations of levan-based polymers in different media, conditions and potential drug delivery systems by using molecular dynamics (MD) simulations. The conformation of levan chains were analyzed in terms of radius of gyration (Rg), end-to-end distance (R), bond length, bond angle, chord length, torsion angle, radial distribution function and mean square displacement. The conformational difference was obtained between single levan chain, multiple levan chain and sulphated levan in different media and temperatures which may affect the biological activity of biopolymers.