Taxonomic group: fungi / Ascomycota
(Phylum: Ascomycota)
Organ / tissue: cell wallAssociated disease: infection due to Aspergillus fumigatus [ICD11:
XN5Z7 
]
NCBI PubMed ID: 32342633Publication DOI: 10.1002/anie.202003951Journal NLM ID: 0370543Publisher: Weinheim: Wiley-VCH
Correspondence: jcodee
chem.leidenuniv.nl
Institutions: IKERBASQUE, Basque Foundation for Science, Bilbao, Spain, Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Derio, Spain, Department Organic Chemistry II, Faculty Science & Technology, EHU-UPV, Leioa, Spain
Galactosaminogalactan (GAG) is a prominent cell wall component of the opportunistic fungal pathogen Aspergillus fumigatus. GAG is a heteropolysaccharide composed of α-1,4-linked galactose, galactosamine and N-acetylgalactosamine residues. To enable biochemical studies, a library of GAG-fragments was constructed featuring specimens containing α-galactose-, α-galactosamine and α-N-acetyl galactosamine linkages. Key features of the synthetic strategy include the use of di-tert-butylsilylidene directed α-galactosylation methodology and regioselective benzoylation reactions using benzoyl-hydroxybenzotriazole (Bz-OBt). Structural analysis of the Gal, GalN and GalNAc oligomers by a combination of NMR and MD approaches revealed that the oligomers adopt an elongated, almost straight, structure, stabilized by inter-residue H-bonds, one of which is a non-conventional C-H-O hydrogen bond between H5 of the residue (i+1) and O3 of the residue (i). The structures position the C-2 substituents almost perpendicular to the oligosaccharide main chain axis, pointing to the bulk solvent and available for interactions with antibodies or other binding partners.
Oligosaccharides, conformational analysis, glycosylation, stereoselectivity, non-conventional hydrogen bond
Structure type: structural motif or average structure
Location inside paper: Fig. 1, A, GAG
Trivial name: galactosaminogalactan, galactosaminogalactan (GAG)
Compound class: cell wall polysaccharide, polysaccharide, galactan, galactosaminogalactan
Contained glycoepitopes: IEDB_130648,IEDB_136906,IEDB_137472,IEDB_137473,IEDB_1391961,IEDB_141584,IEDB_141794,IEDB_151528,IEDB_190606,IEDB_885822,SB_7
Methods: 13C NMR, 1H NMR, NMR-2D, chemical synthesis
NCBI Taxonomy refs (TaxIDs): 746128
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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