Metal ion coordination of macromolecular bioligands: formation of zinc(II) complex of hyaluronic acid

The coordination of zinc(II) ion to hyaluronate (Hya), a natural copolymer, in aqueous solution at pH 6 was investigated by potentiometric and circular dichroism (CD) spectroscopic methods, and by monitoring the changes in macroscopic properties by high-precision measurements. The zinc(II)-selective...

Full description

Saved in:

Bibliographic Details
Published in:	Carbohydrate research Vol. 332; no. 2; pp. 197 - 207
Main Authors:	Burger, Kálmán, Illés, János, Gyurcsik, Béla, Gazdag, Mária, Forrai, Erika, Dékány, Imre, Mihályfi, Katalin
Format:	Journal Article
Language:	English
Published:	Netherlands Elsevier Ltd 18-05-2001
Subjects:	Anion exchange Chromatography, Gel Chromatography, Ion Exchange Circular Dichroism Drug Stability Extra stabilization Hyaluronic Acid - chemistry Hyaluronic acid fragments Ligands Macromolecular Substances Molecular Weight Size-exclusion gel chromatography Sodium Chloride Solutions Static Electricity Viscosity Zinc - chemistry Zinc(II)-hyaluronate complex Zn-selective electrode Zinc(II)-hyaluronate complex V σ, excess volume IEC, anion-exchange chromatography ZnHya, zinc(II) complex of Hya Hya, hyaluronate n̄, degree of the complexation, i.e., bound metal:total ligand concentration ratio Hyaluronic acid fragments Zn-selective electrode M r, molecular weight (Da) τ B, Bingham shear yield value τ, shear stress Anion exchange SEC, size-exclusion gel chromatography D, shear gradient NaHya, sodium salt of Hya Extra stabilization Size-exclusion gel chromatography CD, circular dichroism
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	The coordination of zinc(II) ion to hyaluronate (Hya), a natural copolymer, in aqueous solution at pH 6 was investigated by potentiometric and circular dichroism (CD) spectroscopic methods, and by monitoring the changes in macroscopic properties by high-precision measurements. The zinc(II)-selective electrode, and CD measurements proved the binding of zinc(II) by Hya. A number of Hya fragments ( M r∼3.3×10 3–1.4×10 6) were studied to estimate the contributions of the polyelectrolyte effect, the solvation and host–guest interactions to the extra stabilization of the macromolecular zinc(II) complexes as compared with the monomeric unit. The zinc(II) ion activity increase reflected a stability decrease for the fragments with M r<4×10 4. This molecular weight differs from that where cleavage of the Hya skeleton starts (∼5×10 5, according to the size-exclusion gel, and anion-exchange chromatographic behavior of the Hya fragments) and from that where the polyelectrolyte effect stops (∼6×10 3). The excess volumes and Bingham shear yield values of the solutions revealed the transformation of the coherent random coil structure stabilized by intermolecular association in the NaHya to an intramolecular association producing the globular structure of the ZnHya molecule, with a smaller but more strongly bound solvate water sheet. The binding of Zn(II) by Hya and the rearrangement of the polymer chain, i.e., a size decrease because of the globular structure of the ZnHya molecule, as a consequence of the complex formation was proved.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0008-6215 1873-426X
DOI:	10.1016/S0008-6215(01)00065-9