Taxonomic group: fungi / Ascomycota
(Phylum: Ascomycota)
NCBI PubMed ID: 33043794Publication DOI: 10.1080/19490976.2020.1826761Journal NLM ID: 101495343Publisher: Philadelphia, PA: Taylor & Francis
Correspondence: r.p.singh
nabi.res.in
Institutions: Food and Nutrition Biotechnology Division, National Agri-Food Biotechnology Institute, Mohali, India, Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Mohali, India
β-glucans are the dietary nutrients present in oats, barley, algae, and mushrooms. The macromolecules are well known for their immune-modulatory activity; however, how the human gut bacteria digest them is vaguely understood. In this study, Bacteroides uniformis JCM 13288 T was found to grow on laminarin, pustulan, and porphyran. We sequenced the genome of the strain, which was about 5.05 megabase pairs and contained 4868 protein-coding genes. On the basis of growth patterns of the bacterium, two putative polysaccharide utilization loci for β-glucans were identified from the genome, and associated four putative genes were cloned, expressed, purified, and characterized. Three glycoside hydrolases (GHs) that were endo-acting enzymes (BuGH16, BuGH30, and BuGH158), and one which was an exo-acting (BuGH3) enzyme. The BuGH3, BuGH16, and BuGH158 can cleave linear exo/endo-β-1-3 linkages while BuGH30 can digest endo-β-1-6 linkages. BuGH30 and BuGH158 were further explored for their roles in digesting β-glucans and generation of oligosaccharides, respectively. The BuGH30 predominately found to cleave long chain β-1-6-linked glucans, and obtained final product was gentiobiose. The BuGH158 used for producing oligosaccharides varying from degree of polymerization 2 to 7 from soluble curdlan. We demonstrated that these oligosaccharides can be utilized by gut bacteria, which either did not grow or poorly grew on laminarin. Thus, B. uniformis JCM 13288 T is not only capable of utilizing β-glucans but also shares these glycans with human gut bacteria for potentially maintaining the gut microbial homeostasis.
Enzymes, cross-feeding, glycan utilization, gut bacteria, macroalgae
Structure type: homopolymer
Location inside paper: Fig. 2, D, pustulan
Trivial name: pustulan, β-1,6-glucan, β-1,6-D-glucan, β(1-6)-D-glucan, β-(1,6)-glucan, lasiodiplodan, pustulan, β-(1,6)-glucan, lasiodiplodan, β-(1,6)-glucan, β-(1,6)-glucan, lasiodiplodan, pustulan, β-1,6-glucan, β-(1,6)-glucan, pustulan, β-(1→6)-glucan PCPS, water-soluble glucan (PS-I)
Compound class: EPS, O-polysaccharide, cell wall polysaccharide, glycoprotein, glucan, polysaccharide, cell wall glucoprotein
Contained glycoepitopes: IEDB_135614,IEDB_141806,IEDB_142488,IEDB_146664,IEDB_241101,IEDB_983931,SB_192
Methods: 13C NMR, 1H NMR, NMR-2D, PCR, DNA sequencing, SDS-PAGE, TLC, ELISA, alkaline hydrolysis, enzymatic digestion, affinity chromatography, MALDI-TOF, cloning, cell growth, enzymatic assay, gene expression, DNA extraction, spectrophotometry, Bradford method, centrifugation, DEPT-135, BLASTp, DNS method
Enzymes that release or process the structure: BuGH30 (glycoside hydrolase)
NCBI Taxonomy refs (TaxIDs): 136370Reference(s) to other database(s): GTC:G26777BZ, GlycomeDB:
863, CCSD:
50854, CBank-STR:4234
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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