6FUV

Structure of a manno-oligosaccharide specific solute binding protein, BlMnBP2 from Bifidobacterium animalis subsp. lactis ATCC 27673 in complex with mannotriose

Summary for 6FUV

• Entry DOI: 10.2210/pdb6fuv/pdb
• Descriptor: Solute Binding Protein, BlMnBP1 in complex with mannotriose, beta-D-mannopyranose-(1-4)-beta-D-mannopyranose-(1-4)-beta-D-mannopyranose, TRIETHYLENE GLYCOL, ... (6 entities in total)
• Functional Keywords: abc-transporter, beta-mannotriose, solute binding protein, transport protein
• Biological source: Bifidobacterium
• Total number of polymer chains: 1
• Total formula weight: 49403.56

Authors

Ejby, M.,Abou Hachem, M.,Guskov, A.,Slotboom, D.J. (deposition date: 2018-02-27, release date: 2019-03-20, Last modification date: 2024-05-08)

Primary citation

Ejby, M.,Guskov, A.,Pichler, M.J.,Zanten, G.C.,Schoof, E.,Saburi, W.,Slotboom, D.J.,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., 112:114-130, 2019

PubMed Abstract: 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 β-manno-oligosaccharide (MnOS) ABC transporter in Bifidobacterium animalis subsp. lactis. Despite similar overall specificity and preference to mannotriose (K ≈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.

PubMed: 30947380
DOI: 10.1111/mmi.14257

Experimental method

X-RAY DIFFRACTION (2.001 Å)