Beta-glucosidase (3.2.1.21) plays an essential role in the removal of non-reducing terminal glucosyl residues from glycosides. Recently, beta-glucosidase has been of interest for biomass conversion that acts in synergy with two other enzymes, endoglucanase and exo-glucanase. However, there is not much information available on the catalytic interactions of beta-glucosidase with its substrates. Thus, this study reports on the binding modes between beta-glucosidase from glycoside hydrolase family 1 namely BglB with cellobiose, cellotetraose and cellotetriose via molecular docking simulation. From the results, the binding affinities of BglB-cellobiose, BglB-cellotetraose, and BglB-cellotetriose complexes were reported to be -6.2kJ/mol , -5.68 kJ/mol and -5.63 kJ/mol, respectively. The detail interactions were also been investigated that revealed the key residues involved in forming hydrogen bonds (h-bond) with the substrates. These findings may provide valuable insigths in designing beta-glucosidase with higher cellobiose-hydrolyzing efficiency.

Paenibacillus polymyxa β-glucosidase B (BglB), belongs to a GH family 1, is a monomeric enzyme that acts as an exo-β-glucosidase hydrolysing cellobiose and cellodextrins of higher degree of polymerization using retaining mechanism. A molecular dynamics (MD) simulation was performed at 300 K under periodic boundary condition for 5 ns using the complexes structure obtained from previous docking study, namely BglB-Beta-d-glucose and BglB-Cellobiose. From the root-mean-square deviation analysis, both enzyme complexes were reported to deviate from the initial structure in the early part of the simulation but it was stable afterwards. The root-mean-square fluctuation analysis revealed that the most flexible regions comprised of the residues from 26 to 29, 43 to 53, 272 to 276, 306 to 325 and 364 to 367. The radius of gyration analysis had shown the structure of BglB without substrate became more compact towards the end of the simulation compare to other two complexes. The residues His122 and Trp410 were observed to form stable hydrogen bond with occupancy higher than 10%. In conclusion, the behaviour of BglB enzyme towards the substrate binding was successfully explored via MD simulation approaches.

Beta-glucosidase (3.2.1.21) plays an essential role in the removal of non-reducing terminal glucosyl residues from sacharides and glycosides. Recently, beta-glucosidase has been of interest for biomass conversion that acts in synergy with two other enzymes, endo-glucanase and exoglucanase. However, there is not much information regarding the molecular interactions of beta-glucosidase with cellobiose. Thus, this study reports on the binding modes between beta-glucosidase from glycoside hydrolase family 1 namely BglB with cellobiose and cellotetrose via molecular docking method. Further analysis on the hydrophobic interactions revealed the key residues involved in forming hydrogen bonds (h-bond) with the substrates. The active residue were identified to be Gln22, Glu167, Glu356, Glu402 and Trp402 .These findings may provide valuable insigths in designing beta-glucosidase with higher cellulose-hydrolyzing efficiency. 

Abstract-Beta-glucosidase (3.2.1.21) plays an essential role in the removal of non-reducing terminal glucosyl residues from sacharides and glycosides. Recently, beta-glucosidase has been of interest for biomass conversion that acts in synergy with two other enzymes, endo-glucanase and exo-glucanase. However, there is not much information regarding the molecular interactions of beta-glucosidase with cellobiose. Thus, this study reports on the binding modes between beta-glucosidase from glycoside hydrolase family 1 namely BglB with cellobiose and laminaribiose via molecular docking method. Further analysis on the hydrophobic interactions revealed the key residues involved in forming hydrogen bonds (h-bond) with the substrates. The important residues were reported to be Gln22, Glu167, Tyr298, Glu356, Glu402, and Trp410. These findings may provide valuable insigths in designing beta-glucosidase with higher cellulose-hydrolyzing efficiency.