Structural characterization of an all-aminosugar-containing capsular polysaccharide from Colwellia psychrerythraea 34H

• Published in: Antonie van Leeuwenhoek
• Main Authors: Casillo, Angela, Ståhle, Jonas, Parrilli, Ermenegilda, Sannino, Filomena, Mitchell, Daniel E., Pieretti, Giuseppina, Gibson, Matthew I., Marino, Gennaro, Lanzetta, Rosa, Parrilli, Michelangelo, Widmalm, Göran, Tutino, Maria L., Corsaro, Maria M.
• Format: Text
• Language: English
• Published: 2017
• Subjects: Article; Arctic
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718298/; http://www.ncbi.nlm.nih.gov/pubmed/28161737; https://doi.org/10.1007/s10482-017-0834-6

Colwellia psychrerythraea strain 34H, a Gram-negative bacterium isolated from Arctic marine sediments, is considered a model to study the adaptation to cold environments. Recently, we demonstrated that C. psychrerythraea 34H produces two different extracellular polysaccharides, a capsular polysaccharide and a medium released polysaccharide, which confer cryoprotection to the bacterium. In this study, we report the structure of an additional capsular polysaccharide produced by Colwellia grown at a different temperature. The structure was determined using chemical methods, and one- and two-dimensional NMR spectroscopy. The results showed a trisaccharide repeating unit made up of only amino-sugar residues: N-acetyl-galactosamine, 2,4-diacetamido-2,4,6-trideoxy-glucose (bacillosamine), and 2-acetamido-2-deoxyglucuronic acid with the following structure: →4)-β-d-GlcpNAcA-(1→3)-β-d-QuipNAc4NAc-(1→3)-β-d-GalpNAc-(1→. The 3D model, generated in accordance with 1H,1H-NOE NMR correlations and consisting of ten repeating units, shows a helical structure. In contrast with the other extracellular polysaccharides produced from Colwellia at 4 °C, this molecule displays only a low ice recrystallization inhibition activity.