RRC ID 48438
Author Ejby M, Fredslund F, Andersen JM, Vujičić Žagar A, Henriksen JR, Andersen TL, Svensson B, Slotboom DJ, Abou Hachem M.
Title An ATP Binding Cassette Transporter Mediates the Uptake of α-(1,6)-Linked Dietary Oligosaccharides in Bifidobacterium and Correlates with Competitive Growth on These Substrates.
Journal J Biol Chem
Abstract The molecular details and impact of oligosaccharide uptake by distinct human gut microbiota (HGM) are currently not well understood. Non-digestible dietary galacto- and gluco-α-(1,6)-oligosaccharides from legumes and starch, respectively, are preferentially fermented by mainly bifidobacteria and lactobacilli in the human gut. Here we show that the solute binding protein (BlG16BP) associated with an ATP binding cassette (ABC) transporter from the probiotic Bifidobacterium animalis subsp. lactis Bl-04 binds α-(1,6)-linked glucosides and galactosides of varying size, linkage, and monosaccharide composition with preference for the trisaccharides raffinose and panose. This preference is also reflected in the α-(1,6)-galactoside uptake profile of the bacterium. Structures of BlG16BP in complex with raffinose and panose revealed the basis for the remarkable ligand binding plasticity of BlG16BP, which recognizes the non-reducing α-(1,6)-diglycoside in its ligands. BlG16BP homologues occur predominantly in bifidobacteria and a few Firmicutes but lack in other HGMs. Among seven bifidobacterial taxa, only those possessing this transporter displayed growth on α-(1,6)-glycosides. Competition assays revealed that the dominant HGM commensal Bacteroides ovatus was out-competed by B. animalis subsp. lactis Bl-04 in mixed cultures growing on raffinose, the preferred ligand for the BlG16BP. By comparison, B. ovatus mono-cultures grew very efficiently on this trisaccharide. These findings suggest that the ABC-mediated uptake of raffinose provides an important competitive advantage, particularly against dominant Bacteroides that lack glycan-specific ABC-transporters. This novel insight highlights the role of glycan transport in defining the metabolic specialization of gut bacteria.
Volume 291(38)
Pages 20220-31
Published 2016-9-16
DOI 10.1074/jbc.M116.746529
PII S0021-9258(20)35995-0
PMID 27502277
PMC PMC5025704
MeSH ATP-Binding Cassette Transporters / genetics ATP-Binding Cassette Transporters / metabolism* Bacterial Proteins / genetics Bacterial Proteins / metabolism* Bacteroides / genetics Bacteroides / growth & development Bifidobacterium animalis / genetics Bifidobacterium animalis / growth & development* Humans Oligosaccharides / metabolism*
IF 4.238
Times Cited 14
General Microbes JCM 1217