title: Solution structures of chemoenzymatically synthesized heparin and its precursors.
abstract: We report the first chemoenzymatic synthesis of the stable isotope-enriched heparin from a uniformly labeled [(13)C,(15)N]N-acetylheparosan (-GlcA(1,4)GlcNAc-) prepared from E. coli K5. Glycosaminoglycan (GAG) precursors and heparin were formed from N-acetylheparosan by the following steps: chemical N-deacetylation and N-sulfonation leading to N-sulfoheparosan (-GlcA(1,4)GlcNS-); enzyme-catalyzed C5-epimerization and 2-O-sulfonation leading to undersulfated heparin (-IdoA2S(1,4)GlcNS-); enzymatic 6-O-sulfonation leading to the heparin backbone (-IdoA2S(1,4)GlcNS6S-); and selective enzymatic 3-O-sulfonation leading to the anticoagulant heparin, containing the GlcNS6S3S residue. Heteronuclear, multidimensional nuclear magnetic resonance spectroscopy was employed to analyze the chemical composition and solution structure of [(13)C,(15)N]N-acetylheparosan, precursors, and heparin. Isotopic enrichment was found to provide well-resolved (13)C spectra with the high sensitivity required for conformational studies of these biomolecules. Stable isotope-labeled heparin was indistinguishable from heparin derived from animal tissues and is a novel reagent for studying the interaction of heparin with proteins.
authors.affiliation: Department of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
authors.forename: Zhenqing
authors.initials: Z
authors.lastname: Zhang
authors.forename: Scott A
authors.initials: SA
authors.lastname: McCallum
authors.forename: Jin
authors.initials: J
authors.lastname: Xie
authors.forename: Lidia
authors.initials: L
authors.lastname: Nieto
authors.forename: Francisco
authors.initials: F
authors.lastname: Corzana
authors.forename: Jesús
authors.initials: J
authors.lastname: Jiménez-Barbero
authors.forename: Miao
authors.initials: M
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Linhardt