Interaction of Sulfated Polysaccharides with Counter-Ions

Pass, Geoffrey; Phillips, Glyn O.; Wedlock, D.J.; Morley, R. G.

doi:10.1021/bk-1978-0077.ch017

Cited by 4 publications

(1 citation statement)

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“…In fact, many reactions of glycosaminoglycans are entropy-driven by the ordering and disordering of this water layer [18]. Because each charged group can order several water molecules, an individual glycosaminoglycan chain can be hydrated by several hundred water molecules [42]. This water layer produces a highly hydrophilic environment in the direct vicinity of glycosaminoglycans.…”

Section: Glucuronate N-acetyl Galactosamine 4-sulfatementioning

confidence: 99%

Structure, function, and pathology of proteoglycans and glycosaminoglycans in the urinary tract

Hurst

1994

World J Urol

133

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The roles of glycosaminoglycans and proteoglycans in the physiology of the urinary tract are reviewed. The structures of proteoglycans and glycosaminoglycans are reviewed together with their role in control of epithelial differentiation through stromal-epithelial interactions and as modulators of cytokines. Heparan sulfate proteoglycans appear to be important in maintaining selectivity of the kidney tubular basement membrane, and the majority of the glycosaminoglycan found in the urine appears to come from the upper tract. Evidence suggesting that a dense layer of glycosaminoglycans on the urothelial surface is important to maintaining urothelial impermeability is reviewed and new data showing a high density of proteoglycans on the lumenal surface of the urothelium is presented. The role of this layer in maintaining antibacterial adherence and impermeability was discussed together with data suggesting that failure of this layer is an etiologic factor in interstitial cystitis. A model of the bladder surface is also presented to illustrate the role of proteoglycans and exogenous glycosaminoglycans in the defenses of normal bladder lumen and the failure of these defenses in the interstitial cystitis bladder.

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Section: Glucuronate N-acetyl Galactosamine 4-sulfatementioning

confidence: 99%

Structure, function, and pathology of proteoglycans and glycosaminoglycans in the urinary tract

Hurst

1994

World J Urol

133

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Heavy metal binding to heparin disaccharides. II. First evidence for zinc chelation

Whitfield

Sarkar

1992

Biopolymers

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To map out the heavy metal binding sites of iduronic acid containing oligosaccharides isolated from human kidneys, we studied Zn(II) binding by nuclear magnetic resonance (NMR) and molecular modeling to two disaccharides isolated after nitrous acid depolymerization of heparin and two synthetic disaccharides representative of the heparin structure, namely, IdopA2S (alpha 1,4)AnManOH, 1 alpha, IdopA2S (alpha 1,4)AnManOH6S, 1b, IdopA2S-(alpha 1,4)GlcNS alpha Me, 2a, and IdopA2S (alpha 1,4)GlcNS6S alpha Me, 2b (see previous article in this series). A conformational analysis of the metal free and metal bound solutions was made by comparing calculated [(NOE)]s, [T1]s, and [J]s to experimental values. The 1C4, 4C1, and 2S0 conformations of the L-idopyranosiduronate ring and the 4E and 4T3 of the anhydro-D-mannitol ring are evaluated as are rotations about the C5-C6 hydroxymethylene of the AnManOH(6S) or GlcNS (6S) residues. The NOE between IdopA2S H1 and H3 and the known NOE between H2 and H5, as well as the T1 of IdopA2S H3, are introduced as NMR observables sensitive to the IdopA2S ring conformation. Similarly, a NOE between IdopA2S H5 and AnManOH(6S) or GlcNS(6S) H3 was observed that directly restricts the allowed interglycosidic conformational space. For all disaccharides, the Zn(II) bound spectral data are consistent with models in which these motions are partially "frozen" such that the 1C4 conformation of the IdopA2S is stabilized along with the 4T3 conformation of the AnManOH(6S) ring. The interglycosidic conformation is also stabilized in one of two minima. Electrostatic potential energy calculations gave the best overall agreement with experiment and suggest metal binding conformations with the carboxylate and ring oxygen of the IdopA2S residues (1C4 conformation) and either O3 of the GlcNS(6S) residues or the sulfate oxygens of the 6-sulphate for 2b providing additional chelating sites. These chelation models concur with the observation of marked 13C and 1H NMR chemical shifts for the IdopA2S resonances and of GlcNS H3 for 2 alpha and GlcNS6S C6 for 2b. This study of model compounds implicates the IdopA2S(alpha 1,4)GlcNS6S group as part of the heavy metal binding site in biologically important acidic oligosaccharides such as heparin.

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Investigating the Role of Sulfate Groups for the Binding of Gd³⁺ Ions to Glycosaminoglycans with NMR Relaxometry

et al. 2022

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Glycosaminoglycans (GAGs) are highly negatively charged macromolecules with a large cation binding capacity, but their interaction potential with exogeneous Gd 3 + ions is underinvestigated. These might be released from chelates used as Gadolinium-based contrast agents (GBCAs) for clinical MR imaging due to transmetallation with endogenous cations like Zn 2 + . Recent studies have quantified how an endogenous GAG sequesters released Gd 3 + ions and impacts the thermodynamic and kinetic stability of some GBCAs. In this study, we investigate and compare the chelation ability of two important GAGs (heparin and chondroitin sulfate), as well as the homopolysaccharides dextran and dextran sulfate that are used as models for alternative macromolecular chelators. Our combined ap-proach of MRI-based relaxometry and isothermal titration calorimetry shows that the chelation process of Gd 3 + into GAGs is not just a long-range electrostatic interaction as proposed for the Manning model, but presumably a site-specific binding. Furthermore, our results highlight the crucial role of sulfate groups in this process and indicate that the potential of a specific GAG to engage in this mechanism increases with its degree of sulfation. The transchelation of Gd 3 + ions from GBCAs to sulfated GAGs should thus be considered as one possible explanation for the observed long-term deposition of Gd 3 + in vivo and related observations of long-term signal enhancements on T 1 -weighted MR images.

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Interaction of Sulfated Polysaccharides with Counter-Ions

Cited by 4 publications

References 0 publications

Structure, function, and pathology of proteoglycans and glycosaminoglycans in the urinary tract

Structure, function, and pathology of proteoglycans and glycosaminoglycans in the urinary tract

Heavy metal binding to heparin disaccharides. II. First evidence for zinc chelation

Investigating the Role of Sulfate Groups for the Binding of Gd³⁺ Ions to Glycosaminoglycans with NMR Relaxometry

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Interaction of Sulfated Polysaccharides with Counter-Ions

Cited by 4 publications

References 0 publications

Structure, function, and pathology of proteoglycans and glycosaminoglycans in the urinary tract

Structure, function, and pathology of proteoglycans and glycosaminoglycans in the urinary tract

Heavy metal binding to heparin disaccharides. II. First evidence for zinc chelation

Investigating the Role of Sulfate Groups for the Binding of Gd3+ Ions to Glycosaminoglycans with NMR Relaxometry

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Investigating the Role of Sulfate Groups for the Binding of Gd³⁺ Ions to Glycosaminoglycans with NMR Relaxometry