Anti-GH1 monoclonal antibody, clone 53I8

beta-Glucosidase is the rate-limiting component of a cellulase-hydrolyzing reaction. Thermostability and glucose tolerance are two critical criteria of the enzyme, which practically determine its performance in industrial applications. In this study, a thermostable and glucose-tolerant beta-glucosidase (named Bg11317) belonging to the glycoside hydrolase family I was acquired from a metagenomic library of Turpan soil through functional screening. Bg11317 showed excellent thermostability and glucose-tolerance and its crystal structure was subsequently determined at a high resolution. Rational design based on the structure was conducted, producing three beneficial mutations A397R, L188A and A262S. While A397R improved the cellobiose activity by 80%, L188A and A262S increased the IC50 value of glucose from 0.8 to 1.5 M. The residues that may play a role in glucose-tolerance of GH1 beta-glucosidases were summarized and the performances of glucose-tolerant beta-glucosidases reported in recent years were discussed and compared. This study provides insights into enzymatic properties of Bgl1317 for engineering it into a powerful catalyst and beta-glucosidases in general. (C) 2019 Published by Elsevier B.V.

Comparison of coding nucleotide sequences of the paralogous GH1 and GH2 genes, as well as of the growth hormone amino acid sequences, in the species of closely related salmonid genera Salvelinus, Oncorhynchus, and Salmo was performed. It was demonstrated that, in different groups of salmonids, the amino acid substitution rates were considerably different. In some cases, an obvious discrepancy between the divergence of growth hormone genes and phylogenetic schemes based on other methods and approaches was revealed. These findings suggest that the reason may be multidirectional selection at duplicated genes at different stages of evolution.