Production, characterization, in silico and crystal structure analyses of recombinant endo-β-1,3-glucanase of family 81 glycoside hydrolase (GH81) from Clostridium thermocellum ATCC 27405 and synthesis of laminarioligosaccharides for prebiotic applications

No Thumbnail Available
Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The thermophilic bacterium Clostridium thermocellum contains multienzyme complex called cellulosome which is known to degrade recalcitrant substrates. In this study one of the cellulosomal enzymes, β-1,3-glucanase (CtLam81A) of family 81 GH from Clostridium thermocellum was explored. CtLam81A was highly thermostable and displayed endo β-1,3-glucanase activity. The in silico and X-ray crystal structure of CtLam81A showed N-terminal β-sandwich domain, a (α/α)6 domain and a short β-sandwich domain at C-terminal. Structural analysis of CtLam81A displayed the inverting hydrolytic mechanism. The docking of laminari-oligosaccharides to CtLam81A revealed that the active site can occupy maximum 5 glucose residues of β-1,3-glucan. The aromatic amino acid residues create the binding pocket at active site of CtLam81A to hold the ligand. The laminari-oligosaccharides generated by hydrolysis of curdlan by CtLam81A displayed prebiotic properties. They showed resistance or low digestibility against artificial gastric juice, intestinal fluid and α-amylase than inulin indicating their bioavailability to the probiotic bacteria present in the gastrointestinal tract of human. Therefore, laminari-oligosaccharides can be used for functional food additives.
Description
Supervisor: Arun Goyal
Keywords
BIOSCIENCES AND BIOENGINEERING
Citation