Interplay of pH and binding of multivalent metal ions : Charge inversion and reentrant condensation in protein solutions
(2013) In Journal of Physical Chemistry B 117(18). p.5777-5787- Abstract
Tuning of protein surface charge is a fundamental mechanism in biological systems. Protein charge is regulated in a physiological context by pH and interaction with counterions. We report on charge inversion and the related reentrant condensation in solutions of globular proteins with different multivalent metal cations. In particular, we focus on the changes in phase behavior and charge regulation due to pH effects caused by hydrolysis of metal ions. For several proteins and metal salts, charge inversion as measured by electrophoretic light scattering is found to be a universal phenomenon, the extent of which is dependent on the specific protein-salt combination. Reentrant phase diagrams show a much narrower phase-separated regime for... (More)
Tuning of protein surface charge is a fundamental mechanism in biological systems. Protein charge is regulated in a physiological context by pH and interaction with counterions. We report on charge inversion and the related reentrant condensation in solutions of globular proteins with different multivalent metal cations. In particular, we focus on the changes in phase behavior and charge regulation due to pH effects caused by hydrolysis of metal ions. For several proteins and metal salts, charge inversion as measured by electrophoretic light scattering is found to be a universal phenomenon, the extent of which is dependent on the specific protein-salt combination. Reentrant phase diagrams show a much narrower phase-separated regime for acidic salts such as AlCl3 and FeCl3 compared to neutral salts such as YCl3 or LaCl3. The differences between acidic and neutral salts can be explained by the interplay of pH effects and binding of the multivalent counterions. The experimental findings are reproduced with good agreement by an analytical model for protein charging taking into account ion condensation, metal ion hydrolysis, and interaction with charged amino acid side chains on the protein surface. Finally, the relationship of charge inversion and reentrant condensation is discussed, suggesting that pH variation in combination with multivalent cations provides control over both attractive and repulsive interactions between proteins.
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- author
- Roosen-Runge, Felix LU ; Heck, Benjamin S. ; Zhang, Fajun ; Kohlbacher, Oliver and Schreiber, Frank
- publishing date
- 2013-05-09
- type
- Contribution to journal
- publication status
- published
- in
- Journal of Physical Chemistry B
- volume
- 117
- issue
- 18
- pages
- 11 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:84877710767
- ISSN
- 1520-6106
- DOI
- 10.1021/jp401874t
- language
- English
- LU publication?
- no
- id
- ae52168c-dec1-4135-b83b-18c5dd03fa09
- date added to LUP
- 2018-12-17 09:49:24
- date last changed
- 2022-04-25 19:56:23
@article{ae52168c-dec1-4135-b83b-18c5dd03fa09,
abstract = {{<p>Tuning of protein surface charge is a fundamental mechanism in biological systems. Protein charge is regulated in a physiological context by pH and interaction with counterions. We report on charge inversion and the related reentrant condensation in solutions of globular proteins with different multivalent metal cations. In particular, we focus on the changes in phase behavior and charge regulation due to pH effects caused by hydrolysis of metal ions. For several proteins and metal salts, charge inversion as measured by electrophoretic light scattering is found to be a universal phenomenon, the extent of which is dependent on the specific protein-salt combination. Reentrant phase diagrams show a much narrower phase-separated regime for acidic salts such as AlCl<sub>3</sub> and FeCl<sub>3</sub> compared to neutral salts such as YCl<sub>3</sub> or LaCl<sub>3</sub>. The differences between acidic and neutral salts can be explained by the interplay of pH effects and binding of the multivalent counterions. The experimental findings are reproduced with good agreement by an analytical model for protein charging taking into account ion condensation, metal ion hydrolysis, and interaction with charged amino acid side chains on the protein surface. Finally, the relationship of charge inversion and reentrant condensation is discussed, suggesting that pH variation in combination with multivalent cations provides control over both attractive and repulsive interactions between proteins.</p>}},
author = {{Roosen-Runge, Felix and Heck, Benjamin S. and Zhang, Fajun and Kohlbacher, Oliver and Schreiber, Frank}},
issn = {{1520-6106}},
language = {{eng}},
month = {{05}},
number = {{18}},
pages = {{5777--5787}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Journal of Physical Chemistry B}},
title = {{Interplay of pH and binding of multivalent metal ions : Charge inversion and reentrant condensation in protein solutions}},
url = {{http://dx.doi.org/10.1021/jp401874t}},
doi = {{10.1021/jp401874t}},
volume = {{117}},
year = {{2013}},
}