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Counterion condensation in short cationic peptides: Limiting mobilities beyond the Onsager–Fuoss theory
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SYSNO ASEP 0376619 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Counterion condensation in short cationic peptides: Limiting mobilities beyond the Onsager–Fuoss theory Author(s) Wernersson, Erik (UOCHB-X)
Heyda, Jan (UOCHB-X)
Kubíčková, A. (CZ)
Křížek, T. (CZ)
Coufal, P. (CZ)
Jungwirth, Pavel (UOCHB-X) RID, ORCIDNumber of authors 6 Source Title Electrophoresis. - : Wiley - ISSN 0173-0835
Roč. 33, č. 6 (2012), s. 981-989Number of pages 9 s. Language eng - English Country DE - Germany Keywords background electrolyte effects ; counterion condensation ; ion-pairing ; limiting mobility ; molecular modeling Subject RIV CF - Physical ; Theoretical Chemistry R&D Projects GA203/08/0114 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z40550506 - UOCHB-X (2005-2011) UT WOS 000303155700012 DOI 10.1002/elps.201100602 Annotation We investigated the effect of the background electrolyte (BGE) anions on the electrophoretic mobilities of the cationic amino acids arginine and lysine and the polycationic peptides tetraarginine, tetralysine, nonaarginine, and nonalysine. BGEs composed of sodium chloride, sodium propane-1,3-disulfonate, and sodium sulfate were used. For the amino acids, determination of the limiting mobility by extrapolation, using the OnsagerFuoss (OF) theory expression, yielded consistent estimates. For the peptides, however, the estimates of the limiting mobilities were found to spuriously depend on the BGE salt. This paradox was resolved using molecular modeling. Simulations, on all-atom as well as coarse-grained levels, show that significant counterion condensation, an effect not accounted for in OF theory, occurs for the tetra- and nonapeptides, even for low BGE concentrations. Including this effect in the quantitative estimation of the BGE effect on mobility removed the discrepancy between the estimated limiting mobilities in different salts. The counterion condensation was found to be mainly due to electrostatic interactions, with specific ion effects playing a secondary role. Therefore, the conclusions are likely to be generalizable to other analytes with a similar density of charged groups and OF theory is expected to fail in a predictable way for such analytes. Workplace Institute of Organic Chemistry and Biochemistry Contact asep@uochb.cas.cz ; Kateřina Šperková, Tel.: 232 002 584 ; Jana Procházková, Tel.: 220 183 418 Year of Publishing 2013
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