title: Functional characterization of a gene locus from an uncultured gut Bacteroides conferring xylo-oligosaccharides utilization to Escherichia coli.
abstract: In prominent gut Bacteroides strains, sophisticated strategies have been evolved to achieve the complete degradation of dietary polysaccharides such as xylan, which is one of the major components of the plant cell wall. Polysaccharide Utilization Loci (PULs) consist of gene clusters encoding different proteins with a vast arsenal of functions, including carbohydrate binding, transport and hydrolysis. Transport is often attributed to TonB-dependent transporters, although major facilitator superfamily (MFS) transporters have also been identified in some PULs. However, until now, few of these transporters have been biochemically characterized. Here, we targeted a PUL-like system from an uncultivated Bacteroides species that is highly prevalent in the human gut metagenome. It encodes three glycoside-hydrolases specific for xylo-oligosaccharides, a SusC/SusD tandem homolog and a MFS transporter. We combined PUL rational engineering, metabolic and transcriptional analysis in Escherichia coli to functionally characterize this genomic locus. We demonstrated that the SusC and the MFS transporters are specific for internalization of linear xylo-oligosaccharides of polymerization degree up to 3 and 4 respectively. These results were strengthened by the study of growth dynamics and transcriptional analyses in response to XOS induction of the PUL in the native strain, Bacteroides vulgatus.
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.|TWB, INRA, Ramonville Saint-Agne, France.
authors: Alexandra S
authors: AS
authors: Tauzin
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.
authors: Elisabeth
authors: E
authors: Laville
authors: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
authors: Yao
authors: Y
authors: Xiao
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.
authors: Sébastien
authors: S
authors: Nouaille
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.
authors: Pascal
authors: P
authors: Le Bourgeois
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.
authors: Stéphanie
authors: S
authors: Heux
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.
authors: Jean-Charles
authors: JC
authors: Portais
authors: TWB, INRA, Ramonville Saint-Agne, France.
authors: Pierre
authors: P
authors: Monsan
authors: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
authors: Eric C
authors: EC
authors: Martens
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.
authors: Gabrielle
authors: G
authors: Potocki-Veronese
authors: LISBP, CNRS, INRA, INSAT, Université de Toulouse, Toulouse, France.
authors: Florence
authors: F
authors: Bordes
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001439:Bacteroides / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D000069196:Gastrointestinal Microbiome; D041981:Gastrointestinal Tract / Q000382:microbiology; D006026:Glycoside Hydrolases / Q000378:metabolism; D006801:Humans; D026901:Membrane Transport Proteins / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D013559:Symbiosis; D014995:Xylosidases / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D026901:Membrane Transport Proteins; D009844:Oligosaccharides; D011134:Polysaccharides; D006026:Glycoside Hydrolases; D014995:Xylosidases