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3. 1H- and 13C-NMR studies of solutions of hyaluronic acid esters and salts in methyl sulfoxide: comparison of hydrogen-bond patterns and conformational behaviour

Author

Marco Atzori, Sergio Paoletti, Bjarne J. Kvam, Renato Toffanin, Filippo Biviano, KVAM B., J, Atzori, M, Toffanin, R, Paoletti, Sergio, and Biviano, F.

Subjects
Magnetic Resonance Spectroscopy, Stereochemistry, Molecular Sequence Data, Biochemistry, Medicinal chemistry, Analytical Chemistry, Structure-Activity Relationship, chemistry.chemical_compound, Carbohydrate Conformation, Monosaccharide, Dimethyl Sulfoxide, Hyaluronic Acid, Reduced viscosity, chemistry.chemical_classification, Tetraethylammonium, Hydrogen bond, Chemical shift, Organic Chemistry, Resonance, Esters, Hydrogen Bonding, Sulfoxide, General Medicine, Carbon-13 NMR, Carbohydrate Sequence, chemistry, Salts
Abstract

The 1 H- and 13 C-NMR spectra of the ethyl and benzyl esters and the tetrabutylammonium and tetraethylammonium salts of hyaluronic acid { 2)-β- d -Glc p A-(1 → 3)-β- d -Glc p NAc-(1 n } in Me 2 SO- d 6 have been assigned using 1D and 2D techniques. The chemical shifts of the resonance of GlcNAc C-3 suggest that the relative orientations of the monosaccharides at the (1 → 3) linkage in the esters and salts are different. Small differences in the chemical shifts of the resonance GlcA C-4 suggest only a slight conformational variation around the (1 → 4) linkage. The 13 C-NMR data also suggest similarities in conformation between the esters in Me 2 SO- d 6 and the salts in water. The chemical shifts of the 1 H resonances for NH and OH groups and their temperature dependence for the esters and salts in Me 2 SO reveal markedly stronger inter-residue hydrogen bonds between the carboxyl and NH groups and between HO-4 of GlcA and O-5 of GlcNAc for the salts. The 3 J 2,NH values indicate a slightly different orientation for the acetamido group. For solutions in Me 2 SO, the higher segmental flexibility of the esters is supported by the line widths, whereas the reduced viscosity for the tetrabutylammonium salt showed a sigmoidal concentration dependence and suggests association of chains which could contribute to the segmental rigidity. The linear concentration dependence for the benzyl ester suggests a higher overall flexibility without chain association.

Published
1992
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4. NMR studies of oligosaccharides derived from hyaluronate: complete assignment of 1H and 13C NMR spectra of aqueous di- and tetra-saccharides, and comparison of chemical shifts for oligosaccharides of increasing degree of polymerisation

Author

Sergio Paoletti, Antonella Flaibani, Bjarne J. Kvam, Filippo Biviano, Renato Toffanin, Marco Atzori, Toffanin, R, KVAM B., J, Flaibani, A, Atzori, M, Biviano, F, and Paoletti, Sergio

Subjects
Male, Magnetic Resonance Spectroscopy, Stereochemistry, Molecular Sequence Data, Disaccharide, Hyaluronoglucosaminidase, Oligosaccharides, Disaccharides, Biochemistry, Analytical Chemistry, chemistry.chemical_compound, Testis, Carbohydrate Conformation, Tetrasaccharide, Animals, Hyaluronic Acid, Carbon Isotopes, Aqueous solution, Hydrogen bond, Chemical shift, Organic Chemistry, General Medicine, Carbon-13 NMR, HEXA, chemistry, Carbohydrate Sequence, Two-dimensional nuclear magnetic resonance spectroscopy, Hydrogen
Abstract

A series of oligosaccharides was prepared from hyaluronate by depolymerisation with bovine testicular hyaluronidase. Complete assignment of the 1 H and 13 C NMR spectra was obtained for the disaccharide, the tetrasaccharide, and the NaBH 4 -treated tetrasaccharide, by using various 1D and 2D NMR methods. The 1 H assignments for the tetrasaccharide differ from the incomplete data reported recently (ref. 11). The 13 C NMR spectra of the aqueous di, tetra-, hexa-, and octa-saccharides of this series show that all resonances, apart from those subject to obvious end effects, have chemical shifts comparable to those of the corresponding resonances of hyaluronate in D 2 O. The observed 13 C chemical shifts suggests that cooperative intramolecular hydrogen bonds probably play a minor role in determining the conformation of hyaluronate in water.

Published
1993

5. NMR studies of oligosaccharides derived from hyaluronate: complete assignment of 1H and 13C NMR spectra of aqueous di- and tetra-saccharides, and comparison of chemical shifts for oligosaccharides of increasing degree of polymerisation.

Author

Toffanin R, Kvam BJ, Flaibani A, Atzori M, Biviano F, and Paoletti S

Subjects
Animals, Carbohydrate Conformation, Carbohydrate Sequence, Carbon Isotopes, Disaccharides isolation & purification, Hyaluronoglucosaminidase metabolism, Hydrogen, Magnetic Resonance Spectroscopy methods, Male, Molecular Sequence Data, Oligosaccharides isolation & purification, Testis enzymology, Disaccharides chemistry, Hyaluronic Acid chemistry, Oligosaccharides chemistry
Abstract

A series of oligosaccharides was prepared from hyaluronate by depolymerisation with bovine testicular hyaluronidase. Complete assignment of the 1H and 13C NMR spectra was obtained for the disaccharide, the tetrasaccharide, and the NaBH4-treated tetrasaccharide, by using various 1D and 2D NMR methods. The 1H assignments for the tetrasaccharide differ from the incomplete data reported recently (ref. 11). The 13C NMR spectra of the aqueous di-, tetra-, hexa-, and octa-saccharides of this series show that all resonances, apart from those subject to obvious end effects, have chemical shifts comparable to those of the corresponding resonances of hyaluronate in D2O. The observed 13C chemical shifts suggests that cooperative intramolecular hydrogen bonds probably play a minor role in determining the conformation of hyaluronate in water.

Published
1993
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6. Interaction of a brain extracellular matrix protein with hyaluronic acid.

Author

Perides G, Biviano F, and Bignami A

Subjects
Amino Acid Sequence, Amino Acids analysis, Animals, Carrier Proteins analysis, Carrier Proteins isolation & purification, Cattle, Hyaluronan Receptors, In Vitro Techniques, Molecular Sequence Data, Peptides metabolism, Brain metabolism, Carrier Proteins metabolism, Extracellular Matrix chemistry, Extracellular Matrix Proteins metabolism, Hyaluronic Acid metabolism
Abstract

A glial hyaluronate-binding protein (GHAP) was isolated from bovine spinal cord and partially characterized. Bovine GHAP consisted of three immunologically related polypeptides with molecular masses of 76, 64, and 54 kDa and isoelectric points of 4.1, 4.2, and 4.4, respectively. Peptide mapping and partial amino acid sequencing showed that all three polypeptides derive from the same protein. The protein was localized immunohistochemically with rabbit antisera in the white matter surrounding the myelinated axons. Sugar analyses indicated that the three polypeptides are glycosylated and the sugar residues account for at least 30% of their weight. After enzymatic deglycosylation, the apparent molecular mass of the bovine GHAP was reduced to 43 kDa. The biochemical properties of bovine GHAP were compared to those of human GHAP. Initial peptide mapping indicated similarities between bovine and human GHAP. Partial amino acid sequencing of bovine GHAP showed a striking identity (up to 90%) with human GHAP and with the hyaluronate binding domain of the large human fibroblast proteoglycan, versican. Bovine and human GHAP were demonstrated to bind specifically to hyaluronic acid (HA) with one protein molecule binding to an average 17 disaccharide repeating units. The binding of bovine and human GHAP was inhibited by oligosaccharides of HA and specifically by the octamer. Salt concentrations of up to 1 M NaCl had very little effect on the binding of the GHAP to HA. The GHAP-HA interaction was pH dependent. Dissociation only took place at low pH (less than 3.5). Analysis of several polypeptides derived from GHAP by limited proteolysis allowed us to conclude that one of the tandem repeated sequences is sufficient for HA binding and that the aminoterminal domain (which contains an immunoglobulin-like fold) is not involved in the GHAP-HA-binding event.

Published
1991
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