title: Investigating the relationship between temperature, conformation and calcium binding in heparin model oligosaccharides.
abstract: Glycosaminoglycans such as heparan sulfate (HS) are major components of the cell surface and extracellular matrix (ECM) of all multicellular animals, connecting cells to each other as well as to their environment. The ECM must, therefore, both sense and accommodate changes to external conditions. Heparin, a model compound for HS, responds to increased temperatures, involving changes in the populations of conformational states with implications for the binding of HS to proteins, cations and, potentially, for its activity. A fully13C and15N labelled model octasasccharide; D-GlcNS6S α(1-4) L-IdoA2S [α(1-4) D-GlcNS6S α(1-4) L-IdoA2S]2α(1-4) D-GlcNS6S α(1-4) L-IdoA1,6an, was studied by1H,13C and15N NMR, revealing complex changes in chemical shifts and conformation, over temperatures (280-305 K), comfortably within the range relevant to terrestrial biology. These complex conformational changes indicated an interaction between the carboxylate group of L-iduronate and D-glucosamine residues that was susceptible to temperature changes in this range, while the well-documented hydrogen bond between the N-sulfamido group of glucosamine and the hydroxyl group at position-3 of iduronate remained intact. Unexpectedly, despite the presence of similar thermally-induced conformational changes in a heparin octasaccharide fraction in the sodium ion form, its subsequent binding to calcium ions and their resulting conformation was stringently maintained, as judged by comparisons of1H NMR chemical shifts.
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg 40530, Sweden; Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
authors.forename: Ashley
authors.initials: A
authors.lastname: Hughes
authors.affiliation: Department of Biochemistry, UNIFESP, Rua Três de Maio, Vila Clementino, São Paulo 40440, SP, Brazil.
authors.forename: Maria
authors.initials: M
authors.lastname: Meneghetti
authors.affiliation: Genomics Research Centre, Academia Sinica, No. 128, Section 2, Academia Road, Taipei, Taiwan.
authors.forename: Teng-Yi
authors.initials: TY
authors.lastname: Huang
authors.affiliation: Genomics Research Centre, Academia Sinica, No. 128, Section 2, Academia Road, Taipei, Taiwan.
authors.forename: Shang-Cheng
authors.initials: SC
authors.lastname: Hung
authors.affiliation: Ronzoni Institute for Chemical and Biochemical Research 'G.Ronzoni', Via G.Colombo 81, Milan 20133, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Elli
authors.affiliation: Ronzoni Institute for Chemical and Biochemical Research 'G.Ronzoni', Via G.Colombo 81, Milan 20133, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Guerrini
authors.affiliation: The National Institute of Biological Standards and Controls, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Timothy
authors.initials: T
authors.lastname: Rudd
authors.affiliation: Department of Biochemistry, UNIFESP, Rua Três de Maio, Vila Clementino, São Paulo 40440, SP, Brazil; Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK. Electronic address: mlima@unifesp.br.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Lima
authors.affiliation: Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK; Department of Biochemistry, UNIFESP, Rua Três de Maio, Vila Clementino, São Paulo 40440, SP, Brazil. Electronic address: eayates@liv.ac.uk.
authors.forename: Edwin
authors.initials: E
authors.lastname: Yates
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D006493:Heparin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008968:Molecular Conformation; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D009844:Oligosaccharides; D006493:Heparin; D002118:Calcium
keywords: (13)C; (15)N oligosaccharide; Heparan sulfate; Heparin; Hydrogen bonding; NMR; Octasaccharide