UCT CS Research Document Archive

Conformational properties of two exopolysaccharides produced by Inquilinus limosus, a cystic fibrosis lung pathogen

Kuttel, Michelle, Neil Ravenscroft, Michaela Foschiatti, Paola Cescutti and Roberto Rizzo (2012) Conformational properties of two exopolysaccharides produced by Inquilinus limosus, a cystic fibrosis lung pathogen. Carbohydrate Research 350:40-48.

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Abstract

Inquilinus limosus is a multi-resistant bacterium found in the respiratory tract of patients with cystic fibrosis. This bacterium produces two unique fully pyruvylated exopolysaccharides in similar quantities: an alpha-(1->2)-linked mannan and a beta-(1->3)-linked glucan. We employed molecular modelling methods to probe the characteristic conformations and dynamics of these polysaccharides, with corroboration from potentiometric titrations and circular dichroism experiments. Our calculations reveal different structural motifs for the mannan and glucan polysaccharides: the glucan forms primarily right-handed helices with a wide range of extensions, while the mannan forms only left-handed helices. This finding is supported by our circular dichroism experiments. Our calculations also show that the (1->3)-beta-D-Glcp linkage is more dynamically flexible than the (1->2)-alpha-D-Manp: the glucan characteristically forms a range of wide helices with large central cavities. In contrast, the mannan forms rigid regular ‘bottlebrush’ helices with a minimal central cavity. The widely different character of these two polymers suggests a possible differentiation of biological roles.

EPrint Type:Journal (Paginated)
Keywords:Bacterial exopolysaccharides
Inquilinus limosus
Lung opportunists
Molecular modelling
Carbohydrates
Conformation analysis
Subjects:J Computer Applications: J.3 LIFE AND MEDICAL SCIENCES
J Computer Applications: J.2 PHYSICAL SCIENCES AND ENGINEERING
I Computing Methodologies: I.6 SIMULATION AND MODELING
ID Code:762
Deposited By:Kuttel, Michelle
Deposited On:09 Febuary 2012