TY - JOUR

T1 - Burkholderia cenocepacia h111 produces a water-insoluble exopolysaccharide in biofilm

T2 - Structural determination and molecular modelling

AU - Bellich, Barbara

AU - Jou, Ining A.

AU - Caterino, Marco

AU - Rizzo, Roberto

AU - Ravenscroft, Neil

AU - Fazli, Mustafa

AU - Tolker-Nielsen, Tim

AU - Brady, John W.

AU - Cescutti, Paola

PY - 2020

Y1 - 2020

N2 - Biofilms are a multicellular way of life, where bacterial cells are close together and embedded in a hydrated macromolecular matrix which offers a number of advantages to the cells. Extracellular polysaccharides play an important role in matrix setup and maintenance. A water-insoluble polysaccharide was isolated and purified from the biofilm produced by Burkholderia cenocepacia strain H111, a cystic fibrosis pathogen. Its composition and glycosidic linkages were determined using Gas–Liquid Chromatography–Mass Spectrometry (GLC–MS) on appropriate carbohydrate derivatives while its complete structure was unraveled by 1D and 2D NMR spectroscopy in deuterated sodium hydroxide (NaOD) aqueous solutions. All the collected data demonstrated the following repeating unit for the water-insoluble B. cenocepacia biofilm polysaccharide: [3)-α-d-Galp-(1→3)-α-d-Glcp-(1→3)-α-d-Galp-(1→3)-α-d-Manp-(1→]n Molecular modelling was used, coupled with NMR Nuclear Overhauser Effect (NOE) data, to obtain information about local structural motifs which could give hints about the polysaccharide insolubility. Both modelling and NMR data pointed at restricted dynamics of local conformations which were ascribed to the presence of inter-residue hydrogen bonds and to steric restrictions. In addition, the good correlation between NOE data and calculated interatomic distances by molecular dynamics simulations validated potential energy functions used for calculations.

AB - Biofilms are a multicellular way of life, where bacterial cells are close together and embedded in a hydrated macromolecular matrix which offers a number of advantages to the cells. Extracellular polysaccharides play an important role in matrix setup and maintenance. A water-insoluble polysaccharide was isolated and purified from the biofilm produced by Burkholderia cenocepacia strain H111, a cystic fibrosis pathogen. Its composition and glycosidic linkages were determined using Gas–Liquid Chromatography–Mass Spectrometry (GLC–MS) on appropriate carbohydrate derivatives while its complete structure was unraveled by 1D and 2D NMR spectroscopy in deuterated sodium hydroxide (NaOD) aqueous solutions. All the collected data demonstrated the following repeating unit for the water-insoluble B. cenocepacia biofilm polysaccharide: [3)-α-d-Galp-(1→3)-α-d-Glcp-(1→3)-α-d-Galp-(1→3)-α-d-Manp-(1→]n Molecular modelling was used, coupled with NMR Nuclear Overhauser Effect (NOE) data, to obtain information about local structural motifs which could give hints about the polysaccharide insolubility. Both modelling and NMR data pointed at restricted dynamics of local conformations which were ascribed to the presence of inter-residue hydrogen bonds and to steric restrictions. In addition, the good correlation between NOE data and calculated interatomic distances by molecular dynamics simulations validated potential energy functions used for calculations.

KW - Biofilm exopolysaccharides

KW - Burkholderia cenocepacia H111

KW - Molecular modelling

KW - NMR

KW - Polysaccharide structure

U2 - 10.3390/ijms21051702

DO - 10.3390/ijms21051702

M3 - Journal article

C2 - 32131450

AN - SCOPUS:85081159544

VL - 21

JO - International Journal of Molecular Sciences (Online)

JF - International Journal of Molecular Sciences (Online)

SN - 1661-6596

IS - 5

M1 - 1702

ER -