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Séminaire du Professeur Harry Brumer (UBC, Vancouver)

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Le Professeur Harry Brumer (UBC, Vancouver, Canada) donnera un séminaire à l’amphitéatre Jacques Derrien (Entrée C du bâtiment Polytech-Luminy) le vendredi 29 Mai à 11 heures sur le thème : "Glycans, guts, and PULs : Carbohydrate recognition in dietary fiber utilization"

Résumé : The enzymatic degradation of complex carbohydrates in plant cell walls is essential to the growth and development of diverse organisms in the biosphere, including humans. The limitations of our own genomes make us critically dependent on a massive microbial community residing in our distal gut for the breakdown of the complex carbohydrates commonly known as “dietary fiber.” Notably, this process provides up to 10% of our daily caloric intake and is essential for intestinal health. Commensurate with the tremendous diversity of glycans in our diets, (meta)genomic analysis indicates that the gut microbiota produces vast cohorts of carbohydrate-active enzymes, non-catalytic carbohydrate-binding proteins, sensor/regulators, and transporters central to this process, yet the molecular specificity determinants in these proteins are largely uncharted. Ongoing collaborative work in our group focusses on the functional characterization of Polysaccharide Utilization Loci (PULs) as a paradigm for complex carbohydrate breakdown in the gut ecosystem [1]. Using specific examples, this presentation will highlight how individual PUL proteins have evolved to recognize their cognate substrates, and that PUL complexity scales with glycan complexity in targeting specific polysaccharides [2]. Understanding the dynamic interplay between the manifold monosaccharide- and linkage-specific carbohydrate-active enzymes and binding proteins involved in this process is central to understanding human nutrition, with direct implications for health.

[1] Larsbrink, et al. (2014) A discrete genetic locus confers xyloglucan metabolism in select human gut Bacteroidetes. Nature, 506, 498–502.

[2] Martens, Kelly, Tauzin, Brumer (2014) The devil lies in the details : How variations in polysaccharide fine-structure impact the physiology and evolution of gut microbes. J. Mol. Biol., 426, 3851–3865.