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Human gut microbes express functionally distinct endoglycosidases to metabolize the same N-glycan substrate
- Source :
- Nature Communications, Vol 15, Iss 1, Pp 1-17 (2024)
- Publication Year :
- 2024
- Publisher :
- Nature Portfolio, 2024.
-
Abstract
- Abstract Bacteroidales (syn. Bacteroidetes) are prominent members of the human gastrointestinal ecosystem mainly due to their efficient glycan-degrading machinery, organized into gene clusters known as polysaccharide utilization loci (PULs). A single PUL was reported for catabolism of high-mannose (HM) N-glycan glyco-polypeptides in the gut symbiont Bacteroides thetaiotaomicron, encoding a surface endo-β-N-acetylglucosaminidase (ENGase), BT3987. Here, we discover an ENGase from the GH18 family in B. thetaiotaomicron, BT1285, encoded in a distinct PUL with its own repertoire of proteins for catabolism of the same HM N-glycan substrate as that of BT3987. We employ X-ray crystallography, electron microscopy, mass spectrometry-based activity measurements, alanine scanning mutagenesis and a broad range of biophysical methods to comprehensively define the molecular mechanism by which BT1285 recognizes and hydrolyzes HM N-glycans, revealing that the stabilities and activities of BT1285 and BT3987 were optimal in markedly different conditions. BT1285 exhibits significantly higher affinity and faster hydrolysis of poorly accessible HM N-glycans than does BT3987. We also find that two HM-processing endoglycosidases from the human gut-resident Alistipes finegoldii display condition-specific functional properties. Altogether, our data suggest that human gut microbes employ evolutionary strategies to express distinct ENGases in order to optimally metabolize the same N-glycan substrate in the gastroinstestinal tract.
- Subjects :
- Science
Subjects
Details
- Language :
- English
- ISSN :
- 20411723
- Volume :
- 15
- Issue :
- 1
- Database :
- Directory of Open Access Journals
- Journal :
- Nature Communications
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.be073fb96474aa383a560417efd849c
- Document Type :
- article
- Full Text :
- https://doi.org/10.1038/s41467-024-48802-3