Characterization of Paenibacillus sp. GKG Endo-β-1, 3-Glucanase, a Member of Family 81 Glycoside Hydrolases

Paenibacillus sp. GKG was isolated based on its ability to produce hydrolysis zones on agar plates containing yeast cell wall substrate as the single carbon source. The extracellular enzymes secreted into the culture medium were identified by LC-MS/MS proteomics. Endo-beta-1,3-glucanase PsLam81A containing GH81 catalytic and the CBM56 carbohydrate-binding modules was selected for heterologous expression in Escherichia coli. The identity of the recombinant PsLam81A was confirmed by LC-MS/MS proteomics. The PsLam81A showed the highest activity at 60 degrees C, and the optimal pH range was between 6.5 and 8.0. The analysis of the full-length PsLam81A and truncated PsLam81A Delta CBM56 enzymes showed that the CBM56 module improved the hydrolytic activity towards linear beta-1,3-glucans-curdlan and pachyman but had no effect on hydrolysis of beta-1,3/beta 1,6-branched glucans-laminarin and yeast beta-glucan. The characterization of PsLam81A enzyme broadens current knowledge on the biochemical properties and substrate specificity of family 81 glycoside hydrolases and allows prediction of the necessity of CBM56 module in the process of designing new truncated or chimeric glycosidases.

Automated summary

In this study, a strain called Paenibacillus sp. GKG was isolated and found to produce hydrolysis zones. Proteomic analysis revealed the enzymes secreted by this strain. PsLam81A, an endo-beta-1,3-glucanase containing GH81 catalytic and CBM56 carbohydrate-binding modules, was identified and characterized. It was found that the CBM56 module enhanced the hydrolytic activity of specific substrates.