Beierlein F, Clark T, Braunschweig B, Engelhardt K, Glas L, Peukert W (2015)
Publication Type: Journal article
Publication year: 2015
Book Volume: 119
Pages Range: 5505-5517
Journal Issue: 17
We report a combined experimental and computational study of the whey protein \textgreekb-lactoglobulin (BLG) in different electrolyte solutions. Vibrational sum-frequency generation (SFG) and ellipsometry were used to investigate the molecular structure of BLG modified air-water interfaces as a function of LiCl, NaCl, and KCl concentrations. Molecular dynamics (MD) simulations and thermodynamic integration provided details of the ion pairing of protein surface residues with alkali-metal cations. Our results at pH 6.2 indicate that BLG at the air-water interface forms mono- and bilayers preferably at low and high ionic strength, respectively. Results from SFG spectroscopy and ellipsometry are consistent with intimate ion pairing of alkali-metal cations with aspartate and glutamate carboxylates, which is shown to be more effective for smaller cations (Li(+) and Na(+)). MD simulations show not only carboxylate-alkali-metal ion pairs but also ion multiplets with the alkali-metal ion in a bridging position between two or more carboxylates. Consequently, alkali-metal cations can bridge carboxylates not only within a monomer but also between monomers, thus providing an important dimerization mechanism between hydrophilic surface patches.
APA:
Beierlein, F., Clark, T., Braunschweig, B., Engelhardt, K., Glas, L., & Peukert, W. (2015). Carboxylate Ion Pairing with Alkali-Metal Ions for β-Lactoglobulin and Its Role on Aggregation and Interfacial Adsorption. Journal of Physical Chemistry B, 119(17), 5505-5517. https://doi.org/10.1021/acs.jpcb.5b01944
MLA:
Beierlein, Frank, et al. "Carboxylate Ion Pairing with Alkali-Metal Ions for β-Lactoglobulin and Its Role on Aggregation and Interfacial Adsorption." Journal of Physical Chemistry B 119.17 (2015): 5505-5517.
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