title: Molecular cloning of the heparin/heparan sulfate delta 4,5 unsaturated glycuronidase from Flavobacterium heparinum, its recombinant expression in Escherichia coli, and biochemical determination of its unique substrate specificity.
abstract: The soil bacterium Flavobacterium heparinum produces several enzymes that degrade heparan sulfate glycosaminoglycans (HSGAGs) in a sequence-specific manner. Among others, these enzymes include the heparinases and an unusual glycuronidase that hydrolyzes the unsaturated Delta4,5 uronic acid at the nonreducing end of oligosaccharides resulting from prior heparinase eliminative cleavage. We report here the molecular cloning of the Delta4,5 glycuronidase gene from the flavobacterial genome and its recombinant expression in Escherichia coli as a highly active enzyme. We also report the biochemical and kinetic characterization of this enzyme, including an analysis of its substrate specificity. We find that the Delta4,5 glycuronidase discriminates on the basis of both the glycosidic linkage and the sulfation pattern within its saccharide substrate. In particular, we find that the glycuronidase displays a strong preference for 1-->4 linkages, making this enzyme specific to heparin/heparan sulfate rather than 1-->3 linked glycosaminoglycans such as chondroitin/dermatan sulfate or hyaluronan. Finally, we demonstrate the utility of this enzyme in the sequencing of heparinase-derived HSGAG oligosaccharides.
authors.affiliation: Division of Biological Engineering, Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Myette
authors.forename: Zachary
authors.initials: Z
authors.lastname: Shriver
authors.forename: Tanyel
authors.initials: T
authors.lastname: Kiziltepe
authors.forename: Maitland W
authors.initials: MW
authors.lastname: McLean
authors.forename: Ganesh
authors.initials: G
authors.lastname: Venkataraman
authors.forename: Ram
authors.initials: R
authors.lastname: Sasisekharan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D004187:Disaccharides / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D005417:Flavobacterium / Q000201:enzymology* / Q000235:genetics*; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D005966:Glucuronidase / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D006493:Heparin / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D004187:Disaccharides; D005966:Glucuronidase; D006493:Heparin; D006497:Heparan Sulfate; D009844:Oligosaccharides; D011994:Recombinant Proteins