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dc.rights.licenseCC BY — Creative Commons Attribution
dc.rights.licenseACS Author Choice License
dc.contributor.authorGiubertoni, G.
dc.contributor.authorPérez de Alba Ortíz, A.
dc.contributor.authorBano, F.
dc.contributor.authorZhang, X.
dc.contributor.authorLinhardt, Robert J.
dc.contributor.authorGreen, D.E.
dc.contributor.authorDeAngelis, P.L.
dc.contributor.authorKoenderink, G.H.
dc.contributor.authorRichter, R.P.
dc.contributor.authorEnsing, B.
dc.contributor.authorBakker, H.J.
dc.identifier.citationStrong reduction of the chain rigidity of hyaluronan by selective binding of Ca2+ ions, G. Giubertoni, A. Pérez de Alba Ortíz, F. Bano, X. Zhang, R.J. Linhardt, D. E. Green, P. L. DeAngelis, G.H. Koenderink, R. P. Richter, B. Ensing, and H.J. Bakker, Macromolecules, 54, 1137−1146, 2021.
dc.descriptionMacromolecules, 54, 1137−1146
dc.descriptionNote : if this item contains full text it may be a preprint, author manuscript, or a Gold OA copy that permits redistribution with a license such as CC BY. The final version is available through the publisher’s platform.
dc.description.abstractThe biological functions of natural polyelectrolytes are strongly influenced by the presence of ions, which bind to the polymer chains and thereby modify their properties. Although the biological impact of such modifications is well recognized, a detailed molecular picture of the binding process and of the mechanisms that drive the subsequent structural changes in the polymer is lacking. Here, we study the molecular mechanism of the condensation of calcium, a divalent cation, on hyaluronan, a ubiquitous polymer in human tissues. By combining two-dimensional infrared spectroscopy experiments with molecular dynamics simulations, we find that calcium specifically binds to hyaluronan at millimolar concentrations. Because of its large size and charge, the calcium cation can bind simultaneously to the negatively charged carboxylate group and the amide group of adjacent saccharide units. Molecular dynamics simulations and single-chain force spectroscopy measurements provide evidence that the binding of the calcium ions weakens the intramolecular hydrogen-bond network of hyaluronan, increasing the flexibility of the polymer chain. We also observe that the binding of calcium to hyaluronan saturates at a maximum binding fraction of ∼10–15 mol %. This saturation indicates that the binding of Ca2+ strongly reduces the probability of subsequent binding of Ca2+ at neighboring binding sites, possibly as a result of enhanced conformational fluctuations and/or electrostatic repulsion effects. Our findings provide a detailed molecular picture of ion condensation and reveal the severe effect of a few, selective and localized electrostatic interactions on the rigidity of a polyelectrolyte chain.
dc.description.sponsorshipOklahoma Center for the Advancement of Science and Technology
dc.publisherAmerican Chemical Society (ACS)
dc.relation.ispartofThe Linhardt Research Labs Online Collection
dc.relation.ispartofRensselaer Polytechnic Institute, Troy, NY
dc.rightsAttribution 3.0 United States*
dc.subjectChemistry and chemical biology
dc.subjectChemical and biological engineering
dc.subjectBiomedical engineering
dc.titleStrong reduction of the chain rigidity of hyaluronan by selective binding of Ca2+ ionsen_US
dcterms.accessRightsA full text version is available in DSpace@RPI
dcterms.accessRightsOpen Access
dc.rights.holderCC BY : this license allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. The license allows for commercial use. Credit must be given to the authors and the original work must be properly cited.
dc.relation.departmentThe Linhardt Research Labs.
dc.relation.departmentThe Shirley Ann Jackson, Ph.D. Center for Biotechnology and Interdisciplinary Studies (CBIS)

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