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Publication Abstract from PubMed

The human gut microbiota plays a central role not only in regulating the metabolism of nutrients but also promoting immune homeostasis, immune responses and protection against pathogen colonization. The genome of the Gram-negative symbiont Bacteroides thetaiotaomicron, a dominant member of the human intestinal microbiota, encodes polysaccharide utilization loci PULs, the apparatus required to orchestrate the degradation of a specific glycan. EndoBT-3987 is a key endo-beta-N-acetylglucosaminidase (ENGase) that initiates the degradation/processing of mammalian high-mannose-type (HM-type) N-glycans in the intestine. Here, we provide structural snapshots of EndoBT-3987, including the unliganded form, the EndoBT-3987-Man9GlcNAc2Asn substrate complex, and two EndoBT-3987-Man9GlcNAc and EndoBT-3987-Man5GlcNAc product complexes. In combination with alanine scanning mutagenesis and activity measurements we unveil the molecular mechanism of HM-type recognition and specificity for EndoBT-3987 and an important group of the GH18 ENGases, including EndoH, an enzyme extensively used in biotechnology, and for which the mechanism of substrate recognition was largely unknown.

Structural basis of mammalian high-mannose N-glycan processing by human gut Bacteroides.,Trastoy B, Du JJ, Klontz EH, Li C, Cifuente JO, Wang LX, Sundberg EJ, Guerin ME Nat Commun. 2020 Feb 14;11(1):899. doi: 10.1038/s41467-020-14754-7. PMID:32060313^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.