Enrichment of Two Isomeric Heparin Oligosaccharides Exhibiting Different Affinities toward Monocyte Chemoattractant Protein-1



Miller, RL, Dykstra, AB, Wei, W, Holsclaw, C, Turnbull, JE ORCID: 0000-0002-1791-754X and Leary, JA
(2016) Enrichment of Two Isomeric Heparin Oligosaccharides Exhibiting Different Affinities toward Monocyte Chemoattractant Protein-1. ANALYTICAL CHEMISTRY, 88 (23). 11551 - 11558.

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Abstract

Chemokine-GAG interactions are crucial to facilitate chemokine immobilization, resulting in the formation of chemokine gradients that guide cell migration. Here we demonstrate chromatographic isolation and purification of two heparin hexasaccharide isomers that interact with the oligomeric chemokine Monocyte Chemoattractant Protein-1 (MCP-1)/CCL2 with different binding affinities. The sequences of these two hexasaccharides were deduced from unique MS/MS product ions and HPLC compositional analysis. Ion mobility mass spectrometry (IM-MS) showed that the two isolated oligosaccharides have different conformations and both displayed preferential binding for one of the two distinct conformations known for MCP-1 dimers. A significant shift in arrival time distribution of close to 70 Å2 was observed, indicating a more compact protein:hexasaccharide conformation. Clear differences in the MS spectra between bound and unbound protein allowed calculation of Kd values from the resulting data. The structural difference between the two hexasaccharides was defined as the differential location of a single sulfate at either C-6 of glucosamine or C-2 of uronic acid in the reducing disaccharide, resulting in a 200-fold difference in binding affinity for MCP-1. These data indicate sequence specificity for high affinity binding, supporting the view that sulfate position, and not simply the number of sulfates, is important for heparan sulfate protein binding.

Item Type: Article
Uncontrolled Keywords: anions, oligomers, oligosaccharides, chemical structure, conformation
Depositing User: Symplectic Admin
Date Deposited: 20 Mar 2017 10:09
Last Modified: 26 Nov 2020 19:11
DOI: 10.1021/acs.analchem.6b02803
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URI: http://livrepository.liverpool.ac.uk/id/eprint/3006519

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