Structural and functional analyses of glycoside hydrolase 138 enzymes targeting chain A galacturonic acid in the complex pectin rhamnogalacturonan II.

ABSTRACT: The metabolism of carbohydrate polymers drives microbial diversity in the human gut microbiome. The selection pressures in this environment have spurred the evolution of a complex reservoir of microbial genes encoding carbohydrate-active enzymes (CAZymes). Previously, we have shown that the human gut bacterium Bacteroides thetaiotaomicron (Bt) can depolymerize the most structurally complex glycan, the plant pectin rhamnogalacturonan II (RGII), commonly found in the human diet. Previous investigation of the RGII-degrading apparatus in Bt identified BT0997 as a new CAZyme family, classified as glycoside hydrolase 138 (GH138). The mechanism of substrate recognition by GH138, however, remains unclear. Here, using synthetic substrates and biochemical assays, we show that BT

SUBMITTER: Labourel A 

PROVIDER: S-EPMC6514610 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature