Molecular insights into β-Galactosidase enzyme for its potential application in food industry

Abstract

β-galactosidase generally catalyzes the hydrolysis of β-d-galactosides and α-L-arabinosides. β-galactosidases are well known for its wide range of applications in food industry. In the present study, β-galactosidase from many sources, including archaea, bacteria, fungi, plants, and animals, were analyzed using computational studies such as structural, functional analyses. Sixty sequences were selected for multiple sequence alignment, phylogenetic study, motif and Pfam recognition, identification of physiochemical characteristics. The sequences of β-galactosidase were grouped independently for phylogenetic analysis based on their source. Thermostable proteins were identified through physicochemical analysis. The selected thermostable proteins were then subjected to functional analysis, transmembrane region prediction, secondary structure and domain architecture analysis. The selected highly thermostable sequences were rich in hydrophobic amino acids. Most of the selected β-galactosidase sequences are composed of random coils. The 3D structure of high thermostable bacterial β-galactosidase from Cryobacteriummelibiosiphilum (RJT89331.1) was predicted and the validation results obtained prove that the built structure is of good quality. The modeled structure showed highest similarity with crystal structure of Bifidobacterium longum β-galactosidase. Finally, β-galactosidase from Cryobacterium melibiosiphilum (RJT89331.1) was subjected to docking studies using the CB-DOCK tool with lactose, galactose, galactan, and pectin, with and their binding affinities are −6.6, −5.4, −6.0, −6.4 kJ/mol, respectively. The molecular dynamics simulation was conducted for the docked complex that exhibited the lowest binding energy using NMA (normal mode analysis) to observe the stability and motion of the complex. This computational investigation suggests that the β-galactosidase protein could help in screening β-galactosidase from suitable source for food industry applications.