Taxonomic group: fungi / Basidiomycota
(Phylum: Basidiomycota)
Associated disease: infection due to Cryptococcus neoformans [ICD11:
XN3EH 
]
Publication DOI: 10.1016/j.carres.2005.05.003Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: fzkong
mail.rcees.ac.cn
Institutions: Research Center for Eco-Environmental Sciences, Academia Sinica, PO Box 2871, Beijing 100085, China
β-D-Xylp-(1→2)-α-D-Manp-(1→3)-[β-D-Xylp-(1→2)][β-D-Xylp-(1→4)]-α-D-Manp-(1→3)-[β-D-Xylp-(1→4)]-α-D-Manp, the fragment of the exopolysaccharide from Cryptococcus neoformans serovar C, was synthesized as its methyl glycoside. Thus, chloroacetylation of allyl 3-O-acetyl-4,6-O-benzylidene-α-D-mannopyranoside (1) followed by debenzylidenation and selective 6-O-benzoylation afforded allyl 2-O-chloroacetyl-3-O-acetyl-6-O-benzoyl-α-D-mannopyranoside (4). Glycosylation of 4 with 2,3,4-tri-O-benzoyl-D-xylopyranosyl trichloroacetimidate (5) furnished the β-(1→4)-linked disaccharide 6. Dechloroacetylation gave the disaccharide acceptor 7 and subsequent coupling with 5 produced the trisaccharide 8. Deacetylation of 8 gave the trisaccharide acceptor 9 and subsequent coupling with a disaccharide 10 produced the pentasaccharide 11. Reiteration of deallylation and trichloroacetimidate formation from 11 yielded the pentasaccharide donor 12. Coupling of a disaccharide acceptor 13 with 12 afforded the heptasaccharide 14. Subsequent deprotection gave the heptaoside 16, while selective 2-O-deacetylation of 14 gave the heptasaccharide acceptor 15. Condensation of 15 with glucopyranosyluronate imidate 17 did not yield the expected octaoside, instead, an orthoester product 18 was obtained. Rearrangement of 18 did not give the target octaoside; but produced 15. Meanwhile, there was no reaction between 15 and the glycosyl bromide donor 19.
glucuronic acid, Mannose, Xylose
Structure type: suggested polymer biological repeating unit
Location inside paper: p.1674, fig.1, serotype A
Trivial name: glucuronoxylomannan (GXM)
Compound class: CPS, EPS, O-polysaccharide, O-antigen, cell wall polysaccharide, polysaccharide, glucuronoxylomannan, capsule polysaccharide
Contained glycoepitopes: IEDB_114701,IEDB_115136,IEDB_115576,IEDB_130701,IEDB_140116,IEDB_140630,IEDB_144983,IEDB_145668,IEDB_152206,IEDB_164174,IEDB_167188,IEDB_174332,IEDB_2270799,IEDB_423153,IEDB_76933,IEDB_983930,SB_197,SB_44,SB_67,SB_72
Methods: 13C NMR, 1H NMR, TLC, ESI-MS, chemical synthesis, chemical methods, HPLC, UV, glycosylation
Comments, role: deacetylated structure; chemical repeating unit frame was shifted in annotation for compatibility with structures elucidated by MS [Eukaryotic Cell 2007, 6: 1464-1473]
Related record ID(s): 41246, 41247, 41249, 41250
NCBI Taxonomy refs (TaxIDs): 178876Reference(s) to other database(s): GTC:G75580HK, CCSD:
50376, CBank-STR:15059
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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(later renamed to: Cryptococcus neoformans var. grubii)