In silico approach to investigate the immobilized glucose isomerase from Lactobacillus reuteri using biopolymers

Abstract

Glucose isomerase is one of the isomerase enzymes that convert glucose into fructose. One typical technique to improve enzyme properties is immobilization. Several organic biopolymers including alginate, cellulose, chitin, and chitosan are potentially applied as immobilization agents. Prior to wet lab experiment, in silico analyses were conducted to assess potential activities. This study aimed to analyze glucose isomerase immobilized on alginate, cellulose, chitin, and chitosan via in silico methods. The homology modelling of glucose isomerase from Lactobacillus reuteri was determined using SWISS-MODEL (Expasy). The structure of homology modeling was evaluated via Ramachandran plot (SWISS MODEL) and SAVESv6.1. The constructions of immobilization agents were conducted with GLYCAM website, and the docking was determined using PyRx 0.8 software. Results showed that stereochemical chemistry score was high, with MolProbity of 0.82 and clash score of 0.85, Ramachandran plot resulting in 97.76%, most favored regions, and 0.22% outliers, ERRAT quality factor of 99.344 and Verify3D of 89.76%, with 3D-1D score >= 0.1. Molecular docking showed that alginate was positioned farther from the active, at a distance of 13.232 Å compared to the other agents. Alginate showed the lowest binding affinity among the immobilization agents, with a score of -7.4 kcal/mol. In conclusion, alginate was considered as the most potential immobilization agent among the tested biopolymers others such as cellulose, chitin, and chitosan. Alginate bonded to protein at a position farther from the active site than other agents.