Structural highlights
Publication Abstract from PubMed
Human gut bifidobacteria rely on ATP-binding cassette (ABC) transporters for oligosaccharide uptake. Multiple oligosaccharide-specific solute binding protein (SBP) genes are occasionally associated with a single ABC transporter, but the significance of this multiplicity remains unclear. Here, we characterize BlMnBP1 and BlMnBP2, the two SBPs associated to the beta-manno-oligosaccharide (MnOS) ABC transporter in Bifidobacterium animalis subsp. lactis. Despite similar overall specificity and preference to mannotriose (Kd approximately 80 nM), affinity of BlMnBP1 is up to 2570-fold higher for disaccharides than BlMnBP2. Structural analysis revealed a substitution of an asparagine that recognizes the mannosyl at position 2 in BlMnBP1, by a glycine in BlMnBP2, which affects substrate affinity. Both substitution-types occur in bifidobacterial SBPs, but BlMnBP1-like variants prevail in human-gut isolates. B. animalis subsp. lactis ATCC27673 showed growth on gluco- and galactomannans and was able to outcompete a mannan-degrading Bacteroides ovatus strain in co-cultures, attesting the efficiency of this ABC uptake system. By contrast, a strain that lacks this transporter failed to grow on mannan. This study highlights SBP diversification as a possible strategy to modulate oligosaccharide uptake preferences of bifidobacterial ABC-transporters during adaptation to specific ecological niches. Efficient metabolism of galactomannan by distinct bifidobacteria, merits evaluating this plant glycan as a potential prebiotic. This article is protected by copyright. All rights reserved.
Two binding proteins of the ABC transporter that confers growth of Bifidobacterium animalis subsp. lactis ATCC27673 on beta-mannan possess distinct manno-oligosaccharide binding profiles.,Ejby M, Guskov A, Pichler MJ, Zanten GC, Schoof E, Saburi W, Slotboom DJ, Abou Hachem M Mol Microbiol. 2019 Apr 4. doi: 10.1111/mmi.14257. PMID:30947380[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Ejby M, Guskov A, Pichler MJ, Zanten GC, Schoof E, Saburi W, Slotboom DJ, Abou Hachem M. Two binding proteins of the ABC transporter that confers growth of Bifidobacterium animalis subsp. lactis ATCC27673 on beta-mannan possess distinct manno-oligosaccharide binding profiles. Mol Microbiol. 2019 Apr 4. doi: 10.1111/mmi.14257. PMID:30947380 doi:http://dx.doi.org/10.1111/mmi.14257
