Distinct protein architectures mediate species-specific beta-glucan binding and metabolism in the human gut microbiota
| Autor: | Filip Van Petegem, Guillaume Déjean, Harry Brumer, K. Tamura |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
beta-glucan
0301 basic medicine beta-Glucans complex carbohydrate SusD Biochemistry PUL polysaccharide utilization locus Bacteroides CBM carbohydrate-binding module Glucans carbohydrate-binding module CAZyme carbohydrate-active enzyme TPR tetratricopeptide repeat biology ITC isothermal titration calorimetry polysaccharide utilization locus Editors' Pick dietary fiber Ligand (biochemistry) Tetratricopeptide HGM human gut microbiota Carbohydrate-binding module Bacteroides thetaiotaomicron TBDT TonB-dependent transporter Research Article Glycan Glycoside Hydrolases surface glycan-binding protein Computational biology GUL glucan utilization locus 03 medical and health sciences Bacterial Proteins Species Specificity Tandem repeat Polysaccharides human gut microbiota GH glycoside hydrolase Humans RMSD root-mean-square deviation Molecular Biology 030102 biochemistry & molecular biology Bacteroidetes Membrane Proteins Cell Biology biology.organism_classification Gastrointestinal Microbiome Gastrointestinal Tract SGBP surface glycan-binding protein 030104 developmental biology biology.protein Function (biology) |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 0021-9258 |
| DOI: | 10.1016/j.jbc.2021.100415 |
| Popis: | Complex glycans that evade our digestive system are major nutrients that feed the human gut microbiota (HGM). The prevalence of Bacteroidetes in the HGM of populations worldwide is engendered by the evolution of polysaccharide utilization loci (PULs), which encode concerted protein systems to utilize the myriad complex glycans in our diets. Despite their crucial roles in glycan recognition and transport, cell-surface glycan-binding proteins (SGBPs) remained understudied cogs in the PUL machinery. Here, we report the structural and biochemical characterization of a suite of SGBP-A and SGBP-B structures from three syntenic β(1,3)-glucan utilization loci (1,3GULs) from Bacteroides thetaiotaomicron (Bt), Bacteroides uniformis (Bu), and B. fluxus (Bf), which have varying specificities for distinct β-glucans. Ligand complexes provide definitive insight into β(1,3)-glucan selectivity in the HGM, including structural features enabling dual β(1,3)-glucan/mixed-linkage β(1,3)/β(1,4)-glucan-binding capability in some orthologs. The tertiary structural conservation of SusD-like SGBPs-A is juxtaposed with the diverse architectures and binding modes of the SGBPs-B. Specifically, the structures of the trimodular BtSGBP-B and BuSGBP-B revealed a tandem repeat of carbohydrate-binding module-like domains connected by long linkers. In contrast, BfSGBP-B comprises a bimodular architecture with a distinct β-barrel domain at the C terminus that bears a shallow binding canyon. The molecular insights obtained here contribute to our fundamental understanding of HGM function, which in turn may inform tailored microbial intervention therapies. |
| Databáze: | OpenAIRE |
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