Structural and mutational analysis of glycoside hydrolase family 1 Br2 β-glucosidase derived from bovine rumen metagenome
Issued Date
2023-11-01
Resource Type
ISSN
24058440
Scopus ID
2-s2.0-85176773252
Journal Title
Heliyon
Volume
9
Issue
11
Rights Holder(s)
SCOPUS
Bibliographic Citation
Heliyon Vol.9 No.11 (2023)
Suggested Citation
Kaenying W., Tagami T., Suwan E., Pitsanuwong C., Chomngam S., Okuyama M., Kongsaeree P., Kimura A., Kongsaeree P.T. Structural and mutational analysis of glycoside hydrolase family 1 Br2 β-glucosidase derived from bovine rumen metagenome. Heliyon Vol.9 No.11 (2023). doi:10.1016/j.heliyon.2023.e21923 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/91159
Title
Structural and mutational analysis of glycoside hydrolase family 1 Br2 β-glucosidase derived from bovine rumen metagenome
Author's Affiliation
Other Contributor(s)
Abstract
Ruminant animals rely on the activities of β-glucosidases from residential microbes to convert feed fibers into glucose for further metabolic uses. In this report, we determined the structures of Br2, which is a glycoside hydrolase family 1 β-glucosidase from the bovine rumen metagenome. Br2 folds into a classical (β/α)8-TIM barrel domain but displays unique structural features at loop β5→α5 and α-helix 5, resulting in different positive subsites from those of other GH1 enzymes. Br2 exhibited the highest specificity toward laminaritriose, suggesting its involvement in β-glucan hydrolysis in digested feed. We then substituted the residues at subsites +1 and + 2 of Br2 with those of Halothermothrix orenii β-glucosidase. The C170E and C221T mutations provided favorable interactions with glucooligosaccharide substrates at subsite +2, while the A219N mutation probably improved the substrate preference for cellobiose and gentiobiose relative to laminaribiose at subsite +1. The N407Y mutation increased the affinity toward cellooligosaccharides. These results give further insights into the molecular determinants responsible for substrate specificity in GH1 β-glucosidases and may provide a basis for future enzyme engineering applications.