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

]

NCBI PubMed ID: 19542308
Publication DOI: 10.1128/EC.00013-09
Journal NLM ID: 101130731
Publisher: American Society for Microbiology
Correspondence: de Cock H <h.decock

uu.nl>
Institutions: Microbiology, Institute of Biomembranes, Department of BiologyUtrecht University, CH Utrecht, The Netherlands, Bio-Organic Chemistry, Bijvoet Center, Department of Chemistry, Utrecht University, Utrecht, The Netherlands, Microbiology, Institute of Biomembranes, CH Utrecht, The Netherlands

The human pathogen Cryptococcus neoformans causes meningoencephalitis. The polysaccharide capsule is one of the main virulence factors and consists of two distinct polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM). How capsular polysaccharides are synthesized, transported, and assembled is largely unknown. Previously, it was shown that mutations in the CAP10, CAP59, CAP60, and CAP64 genes result in an acapsular phenotype. Here, it is shown that these acapsular mutants do secrete GalXM and GXM-like polymers. GXM and GalXM antibodies specifically reacted with whole cells and the growth medium of the wild type and CAP mutants, indicating that the capsule polysaccharides adhere to the cell wall and are shed into the environment. These polysaccharides were purified from the medium, either with or without anion-exchange chromatography. Monosaccharide analysis of polysaccharide fractions by gas-liquid chromatography/mass spectrometry showed that wild-type cells secrete both GalXM and GXM. The CAP mutants, on the other hand, were shown to secrete GalXM and GXM-like polymers. Notably, the GalXM polymers were shown to contain glucuronic acid. One-dimensional (1)H nuclear magnetic resonance confirmed that the CAP mutants secrete GalXM and also showed the presence of O-acetylated polymers. This is the first time it is shown that CAP mutants secrete GXM-like polymers in addition to GalXM. The small amount of this GXM-like polymer, 1 to 5% of the total amount of secreted polysaccharides, may explain the acapsular phenotype

Cryptococcus neoformans, Glucuronoxylomannan

Structure type: suggested polymer biological repeating unit ; 1000000-7000000
Location inside paper: fig. 1 (GXM)
Compound class: glucuronoxylomannan
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: 1H NMR, GLC-MS, dot immunoblotting, TLC, GLC, anion-exchange chromatography, CC, immunofluorescence analyses, AEC, propidium iodide staining
Comments, role: Сhemical repeating unit frame was shifted in annotation for compatibility with structures elucidated by MS [Eukaryotic Cell 2007, 6: 1464-1473]

Related record ID(s): 43590
NCBI Taxonomy refs (TaxIDs): 178876
Reference(s) to other database(s): GTC:G34376EY
Show glycosyltransferases

There are 8 chemically distinct structures. Please, select:

*O[C@H]1[C@H](O)[C@@H](CO)O[C@H](O[C@H]2[C@H](O)[C@@H](CO)O[C@H](O[C@H]3[C@H](O)[C@@H](CO)O[C@H](*)[C@H]3O[C@@H]3OC[C@@H](O)[C@H](O)[C@H]3O)[C@H]2O[C@@H]2OC[C@@H](O)[C@H](O)[C@H]2O)[C@H]1O[C@@H]1O[C@H](C(=O)O)[C@@H](O)[C@H](O)[C@H]1O

SVG MW SMILES 3D mol Ionize