{Reference Type}: Journal Article
{Title}: Plant N-glycan breakdown by human gut Bacteroides.
{Author}: Crouch LI;Urbanowicz PA;Baslé A;Cai ZP;Liu L;Voglmeir J;Melo Diaz JM;Benedict ST;Spencer DIR;Bolam DN;Crouch LI;Urbanowicz PA;Baslé A;Cai ZP;Liu L;Voglmeir J;Melo Diaz JM;Benedict ST;Spencer DIR;Bolam DN;
{Journal}: Proc Natl Acad Sci U S A
{Volume}: 119
{Issue}: 39
{Year}: Sep 2022 27
{Factor}: 12.779
{DOI}: 10.1073/pnas.2208168119
{Abstract}: The major nutrients available to the human colonic microbiota are complex glycans derived from the diet. To degrade this highly variable mix of sugar structures, gut microbes have acquired a huge array of different carbohydrate-active enzymes (CAZymes), predominantly glycoside hydrolases, many of which have specificities that can be exploited for a range of different applications. Plant N-glycans are prevalent on proteins produced by plants and thus components of the diet, but the breakdown of these complex molecules by the gut microbiota has not been explored. Plant N-glycans are also well characterized allergens in pollen and some plant-based foods, and when plants are used in heterologous protein production for medical applications, the N-glycans present can pose a risk to therapeutic function and stability. Here we use a novel genome association approach for enzyme discovery to identify a breakdown pathway for plant complex N-glycans encoded by a gut Bacteroides species and biochemically characterize five CAZymes involved, including structures of the PNGase and GH92 α-mannosidase. These enzymes provide a toolbox for the modification of plant N-glycans for a range of potential applications. Furthermore, the keystone PNGase also has activity against insect-type N-glycans, which we discuss from the perspective of insects as a nutrient source.