6mpa
Crystal structure of BlMan5B in complex with GlcNAc (soaking)Crystal structure of BlMan5B in complex with GlcNAc (soaking)
Structural highlights
Publication Abstract from PubMedBifidobacteria represent one of the first colonizers of human gut microbiota, providing to this ecosystem better health and nutrition. To maintain a mutualistic relationship, they have enzymes to degrade and use complex carbohydrates non-digestible by their hosts. To succeed in the densely populated gut environment, they evolved molecular strategies that remain poorly understood. Herein, we report a novel mechanism found in probiotic Bifidobacteria for the depolymerization of the ubiquitous 2-acetamido-2-deoxy-4-O-(beta-d-mannopyranosyl)-d-glucopyranose (Man-beta-1,4-GlcNAc), a disaccharide that composes the universal core of eukaryotic N-glycans. In contrast to Bacteroidetes, these Bifidobacteria have a specialist and strain-specific beta-mannosidase that contains three distinctive structural elements conferring high selectivity for Man-beta-1,4-GlcNAc: a lid that undergoes conformational changes upon substrate binding, a tryptophan residue swapped between the two dimeric subunits to accommodate the GlcNAc moiety, and a Rossmann fold subdomain strategically located near to the active site pocket. These key structural elements for Man-beta-1,4-GlcNAc specificity are highly conserved in Bifidobacterium species adapted to the gut of a wide range of social animals, including bee, pig, rabbit, and human. Together, our findings uncover an unprecedented molecular strategy employed by Bifidobacteria to selectively uptake carbohydrates from N-glycans in social hosts. N-glycan Utilization by Bifidobacterium Gut Symbionts Involves a Specialist beta-Mannosidase.,Cordeiro RL, Pirolla RAS, Persinoti GF, Gozzo FC, de Giuseppe PO, Murakami MT J Mol Biol. 2019 Jan 11. pii: S0022-2836(19)30006-3. doi:, 10.1016/j.jmb.2018.12.017. PMID:30641082[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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