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Binding of charged ligands to macromolecules. Anomalous salt dependence

da Silva, Fernando Luis B; Linse, Sara LU and Jönsson, Bo LU (2005) In The Journal of Physical Chemistry Part B 109(5). p.2007-2013
Abstract
Although interactions in biological systems occur in the presence of a large number of charged species, the binding of charged ligands to different biomolecules is often analyzed in a simplified model focusing only upon the receptor, ligand, and added salt. Here we demonstrate that the presence of charged macromolecules can affect binding to the receptor in an unexpected way. Experimental studies of the binding of barium ions to the chelator5,5'-dibromo-1,2-bis(O-amino-phenoxy)-ethane-N,N,N',N'-tetraacetic acid in the presence of charged silica sols show that the binding affinity increases with added salt. The experimental findings are verified in Monte Carlo simulations using a dielectric continuum model with a uniform dielectric... (More)
Although interactions in biological systems occur in the presence of a large number of charged species, the binding of charged ligands to different biomolecules is often analyzed in a simplified model focusing only upon the receptor, ligand, and added salt. Here we demonstrate that the presence of charged macromolecules can affect binding to the receptor in an unexpected way. Experimental studies of the binding of barium ions to the chelator5,5'-dibromo-1,2-bis(O-amino-phenoxy)-ethane-N,N,N',N'-tetraacetic acid in the presence of charged silica sols show that the binding affinity increases with added salt. The experimental findings are verified in Monte Carlo simulations using a dielectric continuum model with a uniform dielectric permittivity throughout the solution. The anomalous salt behavior is caused by a reduction of the chemical potential of the free ligand, which even in the absence of binding interacts strongly with the oppositely charged receptor. These results are also relevant for the interpretation of competition studies often used in the case of strong ligand binding. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
109
issue
5
pages
2007 - 2013
publisher
The American Chemical Society
external identifiers
  • wos:000226779900051
  • scopus:13444257969
ISSN
1520-5207
DOI
10.1021/jp049304o
language
English
LU publication?
yes
id
10dca575-57af-424f-8ae6-25f5dd5373c9 (old id 151561)
date added to LUP
2007-06-29 15:25:58
date last changed
2017-11-05 04:34:02
@article{10dca575-57af-424f-8ae6-25f5dd5373c9,
  abstract     = {Although interactions in biological systems occur in the presence of a large number of charged species, the binding of charged ligands to different biomolecules is often analyzed in a simplified model focusing only upon the receptor, ligand, and added salt. Here we demonstrate that the presence of charged macromolecules can affect binding to the receptor in an unexpected way. Experimental studies of the binding of barium ions to the chelator5,5'-dibromo-1,2-bis(O-amino-phenoxy)-ethane-N,N,N',N'-tetraacetic acid in the presence of charged silica sols show that the binding affinity increases with added salt. The experimental findings are verified in Monte Carlo simulations using a dielectric continuum model with a uniform dielectric permittivity throughout the solution. The anomalous salt behavior is caused by a reduction of the chemical potential of the free ligand, which even in the absence of binding interacts strongly with the oppositely charged receptor. These results are also relevant for the interpretation of competition studies often used in the case of strong ligand binding.},
  author       = {da Silva, Fernando Luis B and Linse, Sara and Jönsson, Bo},
  issn         = {1520-5207},
  language     = {eng},
  number       = {5},
  pages        = {2007--2013},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Binding of charged ligands to macromolecules. Anomalous salt dependence},
  url          = {http://dx.doi.org/10.1021/jp049304o},
  volume       = {109},
  year         = {2005},
}