Work

Misincorporation of Galactose by Chondroitin Synthase of Escherichia coli K4: From Traces to Synthesis of Chondbiuronan, a Novel Chondroitin-Like Polysaccharide

Year: 2020

Type: article

Abstract: Chondroitin synthase KfoC is a bifunctional enzyme which polymerizes the capsular chondroitin backbone of Escherichia coli K4, composed of repeated β3N-acetylgalactosamine (GalNAc)-β4-glucuronic acid (GlcA) units. Sugar donors UDP-GalNAc and UDP-GlcA are the natural precursors of bacterial chondroitin synthesis. We have expressed KfoC in a recombinant strain of Escherichia coli deprived of 4-epimerase activity, thus incapable of supplying UDP-GalNAc in the bacterial cytoplasm. The strain was also co-expressing mammal galactose β-glucuronyltransferase, providing glucuronyl-lactose from exogenously added lactose, serving as a primer of polymerization. We show by the mean of NMR analyses that in those conditions, KfoC incorporates galactose, forming a chondroitin-like polymer composed of the repeated β3-galactose (Gal)-β4-glucuronic acid units. We also show that when UDP-GlcNAc 4-epimerase KfoA, encoded by the K4-operon, was co-expressed and produced UDP-GalNAc, a small proportion of galactose was still incorporated into the growing chain of chondroitin.

Source: Biomolecules

DOI: 10.3390/biom10121667

Authors: Mélanie Leroux, Julie Michaud, Eric Bayma, Sylvie Armand, Sophie Drouillard, Bernard Priem

Institutions: Centre National de la Recherche Scientifique, Centre de Recherches sur les Macromolécules Végétales, Université Grenoble Alpes

Language: English

Topic: Proteoglycans and glycosaminoglycans research

Subfield: Cell Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: gold

Estimated APC paid: $1,901

Funder: Agence Nationale de la Recherche