Maximizing Yield and Modification of 13C/15N Labeled Heparosan From E. coli K5 Culture

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Description
Understanding glycosaminoglycans’ (GAG) interaction with proteins is of growing interest for therapeutic applications. For instance, heparin is a GAG exploited for its ability to inhibit proteases, therefore inducing anticoagulation. For this reason, heparin is extracted in mass quantities from porcine

Understanding glycosaminoglycans’ (GAG) interaction with proteins is of growing interest for therapeutic applications. For instance, heparin is a GAG exploited for its ability to inhibit proteases, therefore inducing anticoagulation. For this reason, heparin is extracted in mass quantities from porcine intestine in the pharmaceutical field. Following a contamination in 2008, alternative sources for heparin are desired. In response, much research has been invested in the extraction of the naturally occurring polysaccharide, heparosan, from Escherichia coli K5 strain. As heparosan contains the same structural backbone as heparin, modifications can be made to produce heparin or heparin-like molecules from this source. Furthermore, isotopically labeled batches of heparosan can be produced to aid in protein-GAG interaction studies. In this study, a comparative look between extraction and purification methods of heparosan was taken. Fed-batch fermentation of this E. coli strain followed by subsequent purification yielded a final 13C/15N labeled batch of 90mg/L of heparosan which was then N-sulfated. Furthermore, a labeled sulfated disaccharide from this batch was utilized in a protein interaction study with CCL5. With NMR analysis, it was found that this heparin-like molecule interacted with CCL5 when its glucosamine residue was in a β-conformation. This represents an interaction reliant on a specific anomericity of this GAG molecule.
Date Created
2015-05
Agent

Structural Mechanisms Underlying Sequence-Dependent Variations in GAG Affinities of Decorin Binding Protein A, a Borrelia Burgdorferi Adhesin

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Description

Structural mechanisms behind variations in glycosaminoglycan (GAG) affinities of decorin-binding protein As (DBPAs) from different Borrelia strains were investigated using NMR. DBPA from strain PBr was revealed to have an additional GAG-binding epitope and a retracted linker allowing more access to its GAG-binding sites.

Date Created
2015-05-01
Agent