Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Brucella abortus [ICD11:
XN7A8 
]
The structure was elucidated in this paperNCBI PubMed ID: 17921247Journal NLM ID: 7505876Publisher: National Academy of Sciences
Institutions: Instituto de Investigaciones Biotecnologicas, Universidad Nacional de General San Martin, 1650 Buenos Aires, Argentina
Cyclic β-1,2-glucans (CβG) are osmolyte homopolysaccharides with a cyclic β-1,2-backbone of 17-25 glucose residues present in the periplasmic space of several bacteria. Initiation, elongation, and cyclization, the three distinctive reactions required for building the cyclic structure, are catalyzed by the same protein, the CβG synthase. The initiation activity catalyzes the transference of the first glucose from UDP-glucose to a yet-unidentified amino acid residue in the same protein. Elongation proceeds by the successive addition of glucose residues from UDP-glucose to the nonreducing end of the protein-linked β-1,2-oligosaccharide intermediate. Finally, the protein-linked intermediate is cyclized, and the cyclic glucan is released from the protein. These reactions do not explain, however, the mechanism by which the number of glucose residues in the cyclic structure is controlled. We now report that control of the degree of polymerization (DP) is carried out by a β-1,2-glucan phosphorylase present at the CβG synthase C-terminal domain. This last activity catalyzes the phosphorolysis of the β-1,2-glucosidic bond at the nonreducing end of the linear protein-linked intermediate, releasing glucose 1-phosphate. The DP is thus regulated by this 'length-controlling' phosphorylase activity. To our knowledge, this is the first description of a control of the DP of homopolysaccharides
glycosyltransferases, mechanism, Bacillus, beta-Glucanscyclic, degree of polymerization, cyclic β-1, 2-glucan, size control
Structure type: cyclic polymer repeating unit
Location inside paper: p.16492
Trivial name: cyclosophoran, cyclic β-1,2-glucan, cyclic (β 1-2)-D-glucan, cyclic b-(1,2)-glucan
Compound class: CPS, EPS, LOS
Contained glycoepitopes: IEDB_140628,IEDB_142488,IEDB_146664,IEDB_983931,SB_192
Methods: MALDI-TOF MS, genetic methods, biochemical methods, HPAEC-PAD
Biological activity: phosphorylase activity
Enzymes that release or process the structure: Cgs (cyclic b-1,2-glucan synthase)
Biosynthesis and genetic data: genetic data
Synthetic data: enzymatic
NCBI Taxonomy refs (TaxIDs): 358,
235Reference(s) to other database(s): GTC:G21553SY, GlycomeDB:
25048
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There is only one chemically distinct structure:
Found 
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