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Taxonomic group: fungi / Basidiomycota (Phylum: Basidiomycota)
Associated disease: infection due to Cryptococcus neoformans [ICD11: XN3EH

]; infection due to Cryptococcus gattii [ICD11: XN0LE

]

NCBI PubMed ID: 1446309
Journal NLM ID: 0043535
Publisher: Elsevier
Institutions: Department of Chemistry, Georgia State University, Atlanta 30303

Cryptococcus neoformans, the etiologic agent of cryptococcal meningoencephalitis, produces glucuronoxylomannan (GXM) as the major capsule component. Purified GXMs obtained from eight serotype A isolates of C. neoformans were treated by ultrasonic irradiation and then O-deacetylated prior to their comprehensive chemical analysis by GLC, GLC-MS, and 13C NMR spectroscopy. The average xylose: mannose: glucuronic acid molar ratio of the eight isolates is 1.96 +/- 0.25: 3.00: 0.58 +/- 0.10. Methylation analyses and 13C NMR spectroscopy show a general structure for GXM that is comprised of a linear (1----3)-α-D-mannopyranan substituted with β-D-GlcpA and with β-D-Xylp at O-2. Variable quantities of unsubstituted (1----3)-α-D-manp were observed between the eight isolates studied. In several isolates some of the (1----3)-α-D-manp residues are disubstituted with β-D-GlcpA at O-2 and with β-D-Xylp at O-4; this type of substitution was not previously thought to occur in serotype A isolates. Heterogeneity, between isolates, in the disposition of the substituents along the mannopyranan backbone was revealed by 13C NMR spectroscopy. The eight isolates, and three isolates previously studied, were each assigned to one of four distinct groups based on the 13C NMR chemical shifts of the anomeric carbons. Six of the eleven isolates gave identical spectra (Group I). The six major anomeric resonances from Group I were assigned to specific glycosidic linkages present in GXM. The remaining five isolates gave more complex spectra that are indicative of additional linkages and comprise the remaining three groups. Three of these five isolates contain substantial amounts of linkages previously thought to be distinctive of serotypes B and C, i.e., Manp residues that are 4-O-glycosylated with β-D-Xylp. Methylation analyses only predicted an average repeating unit, whereas 13C NMR spectroscopy demonstrated that GXM from each isolate may be categorized into four groups by the occurrence of distinct sequences of carbohydrate residues.

Structure type: polymer chemical repeating unit
Location inside paper: 3, serotype B
Trivial name: glucuronoxylomannan (GXM)
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, GLC-MS, acid hydrolysis, GLC, methylation analysis, ion-exchange CC
Comments, role: suggested structure with an unassigned region of low intensity

Related record ID(s): 116826, 116827, 116829, 116830, 116831, 116832
NCBI Taxonomy refs (TaxIDs): 37769
Reference(s) to other database(s): GTC:G01581BT, CCSD:24528, CBank-STR:20986
Show glycosyltransferases

There is only one chemically distinct structure:

*O[C@H]1[C@H](O)[C@@H](CO)O[C@H](O[C@@H]2[C@H](O[C@@H]3OC[C@@H](O)[C@H](O)[C@H]3O)[C@@H](O[C@@H]3[C@H](O[C@@H]4O[C@H](C(=O)O)[C@@H](O)[C@H](O)[C@H]4O)[C@@H](O[C@@H]4[C@H](O[C@@H]5OC[C@@H](O)[C@H](O)[C@H]5O)[C@@H](O[C@@H]5[C@H](O[C@@H]6OC[C@@H](O)[C@H](O)[C@H]6O)[C@@H](O[C@@H]6[C@H](O[C@@H]7O[C@H](C(=O)O)[C@@H](O)[C@H](O)[C@H]7O)[C@@H](O[C@@H]7[C@H](O)[C@@H](O[C@@H]8[C@H](O)[C@@H](O[C@@H]9[C@H](O[C@@H]%10OC[C@@H](O)[C@H](O)[C@H]%10O)[C@@H](O[C@@H]%10[C@H](O[C@@H]%11OC[C@@H](O)[C@H](O)[C@H]%11O)[C@@H](O[C@H]%11[C@H](O)[C@@H](CO)O[C@H](*)[C@H]%11O[C@@H]%11O[C@H](C(=O)O)[C@@H](O)[C@H](O)[C@H]%11O)O[C@H](CO)[C@H]%10O)O[C@H](CO)[C@H]9O)O[C@H](CO)[C@H]8O)O[C@H](CO)[C@H]7O)O[C@H](CO)[C@H]6O[C@@H]6OC[C@@H](O)[C@H](O)[C@H]6O)O[C@H](CO)[C@H]5O)O[C@H](CO)[C@H]4O)O[C@H](CO)[C@H]3O[C@@H]3OC[C@@H](O)[C@H](O)[C@H]3O)O[C@H](CO)[C@H]2O)[C@H]1O[C@@H]1OC[C@@H](O)[C@H](O)[C@H]1O

SVG MW SMILES 3D mol Ionize