Cepacian is an exopolysaccharide produced by the majority of the isolates belonging to the Burkholderia cepacia complex bacteria, a group of 17 species, some of which infect cystic fibrosis patients, sometime with fatal outcome. The repeating unit of cepacian consists of a backbone having a trisaccharidic repeating unit with three side chains, as reported in the formula below. The exopolysaccharide is also acetylated, carrying from one to three acetyl esters per repeating unit, depending on the strain examined. The consequences of O-acetyl substitution in a polysaccharide are important both for its biological functions and for industrial applications, including the preparation of conjugated vaccines, since O-acetyl groups are important immunogenic determinants. The location of acetyl groups was achieved by NMR spectroscopy and ESI mass spectrometry and revealed that these substituents are scattered in non-stoichiometric ratio on many sugar residues in different positions, a feature which adds to the already unique carbohydrate structure of the polysaccharide.
NMR, polysaccharide structure, ESI-MS, cystic fibrosis, O-Acetyl groups, Burkholderia cepacia complex
NCBI PubMed ID: 22055818Publication DOI: 10.1016/j.carres.2011.10.011Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: pcescutti@units.it
Institutions: Dipartimento di Scienze della Vita, Università di Trieste, via L. Giorgieri 1, 34134 Trieste, Italy, Istituto di Chimica e Tecnologia dei Polimeri, Via Paolo Gaifami 18, 95126 Catania, Italy
Methods: 13C NMR, 1H NMR, NMR-2D, sugar analysis, enzymatic hydrolysis, ESI-MS, de-O-acetylation
Found