Structural basis of mammalian high-mannose N-glycan processing by human gut Bacteroides
Authors/Creators
- 1. Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain
- 2. Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- 3. Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. Program in Molecular Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- 4. Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA
- 5. Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- 6. Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain. IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
Description
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-β-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.
Files
s41467-020-14754-7.pdf
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