Draft genome analysis of lignocellulolytic enzymes producing Aspergillus terreus with structural insight of β-glucosidases through molecular docking approach.

Members of the genus Aspergillus are extensively studied ascomycetes because of their ability to synthesize high value-added compounds and enzymes of industrial interest. Precise whole genome assembly and gene annotation are significant for gene functional analyses. Here, we report the draft genome sequencing, assembly and whole genome analysis of Aspergillus terreus P14_T3, isolated from rumen sample of cattle fed with coconut-coir. A total of 13,340 protein-coding genes were predicted, among them 493 are involved in degradation of complex carbohydrate polysaccharides. Further, it was found that 29 genes, encoding β-glucosidase belong to Glycosyl hydrolase (GH) family 1 (3 gene), 3 (17 gene), 5 (4 gene), 17 (3 gene), 132 (2 gene). The tertiary structure of all the β-glucosidases was designed by homology modeling; modeled structure AtBgl1.3 (GH1), AtBgl3.1 (GH3), AtBgl5.4 (GH5), AtBgl17.1 (GH17) show classical (α/β) TIM-like barrel motif. Molecular docking of different β-glucosidases with cellobiose revealed that conserved amino acids i.e. Glu, Trp, Arg, His, Tyr and Asp are taking part in substrate hydrolysis. Moreover, some other amino acids i.e. Ser, Phe, Gln and Asn are found to be involved in hydrogen bond formation and catalysis. These findings may provide valuable insights in designing β-glucosidases with higher cellulose-hydrolyzing efficiency.