Molecular interaction of linear and branched fructans of different sizes with levansucrase and inulosucrase from Lactobacillus gasseri: modeling and computational analysis

Abstract

Human beings consume probiotics and prebiotics because of the health benefits they provide. Lactobacillus gasseri is a probiotic microorganism native to humans which produces glycolytic enzymes directed at the hydrolysis of soluble fibers as prebiotic fructans. In this work, levansucrase (LevG) and inulosucrase (InuGB) from L. gasseri were used to predict the ability of L. gasseri to interact with linear and branched fructans prebiotics (inulin and agavins). AlphaFold and SWISS-MODEL were the servers used for tertiary structure prediction of LevG and InuGB, and fructans with different degrees of polymerization (DP2, DP4 DP6, DP8, DP12 and DP20) were used to generate ligand-enzyme molecular dockings by AutodockVina, GlycoTorchVina, and Autodock FR software. The best affinity energies obtained by molecular docking were obtained with agavin and inulin with a DP of 6 and 8 units. Aspartic acid, glutamic acid, asparagine and arginin are the main amino acids involved in the interaction with these substrates. At the same time, the binding pocket shows hydrophilic characteristics; GlycoTorchVina was the best software for protein-ligand docking. These results demonstrate the ability of L. gasseri enzymes to interact with different molecular structures of fructans; levansucrase with better affinity to agavin and inulosucrase with better affinity to inulin. The above helps to understand the structure-functionality relationship of the prebiotic effect, both in symbiotic formulations and in the human digestive tract.