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Concentration-Induced Association in a Protein System Caused by a Highly Directional Patch Attraction

Li, Weimin LU ; Persson, Björn A. LU ; Lund, Mikael LU ; Bergenholtz, Johan and Zackrisson, Malin LU (2016) In Journal of Physical Chemistry B 120(34). p.8953-8959
Abstract

Self-association of the protein lactoferrin is studied in solution using small-angle X-ray scattering techniques. Effective static structure factors have been shown to exhibit either a monotonic or a nonmonotonic dependence on protein concentration in the small wavevector limit, depending on salt concentration. The behavior correlates with a nonmonotonic dependence of the second virial coefficient on salt concentration, such that a maximum appears in the structure factor at a low protein concentration when the second virial coefficient is negative and close to a minimum. The results are interpreted in terms of an integral equation theory with explicit dimers, formulated by Wertheim, which provides a consistent framework able to explain... (More)

Self-association of the protein lactoferrin is studied in solution using small-angle X-ray scattering techniques. Effective static structure factors have been shown to exhibit either a monotonic or a nonmonotonic dependence on protein concentration in the small wavevector limit, depending on salt concentration. The behavior correlates with a nonmonotonic dependence of the second virial coefficient on salt concentration, such that a maximum appears in the structure factor at a low protein concentration when the second virial coefficient is negative and close to a minimum. The results are interpreted in terms of an integral equation theory with explicit dimers, formulated by Wertheim, which provides a consistent framework able to explain the behavior in terms of a monomer-dimer equilibrium that appears because of a highly directional patch attraction. Short attraction ranges preclude trimer formation, which explains why the protein system behaves as if it were subject to a concentration-dependent isotropic protein-protein attraction. Superimposing an isotropic interaction, comprising screened Coulomb repulsion and van der Waals attraction, on the patch attraction allows for a semiquantitative modeling of the complete transition pathway from monomers in the dilute limit to monomer-dimer systems at somewhat higher protein concentrations.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry B
volume
120
issue
34
pages
7 pages
publisher
The American Chemical Society
external identifiers
  • scopus:84985955482
  • wos:000382596700021
ISSN
1520-6106
DOI
10.1021/acs.jpcb.6b06873
language
English
LU publication?
yes
id
19f47cd1-b846-43ea-b89a-c610b359495a
date added to LUP
2016-11-11 15:34:53
date last changed
2017-11-05 05:09:22
@article{19f47cd1-b846-43ea-b89a-c610b359495a,
  abstract     = {<p>Self-association of the protein lactoferrin is studied in solution using small-angle X-ray scattering techniques. Effective static structure factors have been shown to exhibit either a monotonic or a nonmonotonic dependence on protein concentration in the small wavevector limit, depending on salt concentration. The behavior correlates with a nonmonotonic dependence of the second virial coefficient on salt concentration, such that a maximum appears in the structure factor at a low protein concentration when the second virial coefficient is negative and close to a minimum. The results are interpreted in terms of an integral equation theory with explicit dimers, formulated by Wertheim, which provides a consistent framework able to explain the behavior in terms of a monomer-dimer equilibrium that appears because of a highly directional patch attraction. Short attraction ranges preclude trimer formation, which explains why the protein system behaves as if it were subject to a concentration-dependent isotropic protein-protein attraction. Superimposing an isotropic interaction, comprising screened Coulomb repulsion and van der Waals attraction, on the patch attraction allows for a semiquantitative modeling of the complete transition pathway from monomers in the dilute limit to monomer-dimer systems at somewhat higher protein concentrations.</p>},
  author       = {Li, Weimin and Persson, Björn A. and Lund, Mikael and Bergenholtz, Johan and Zackrisson, Malin},
  issn         = {1520-6106},
  language     = {eng},
  month        = {09},
  number       = {34},
  pages        = {8953--8959},
  publisher    = {The American Chemical Society},
  series       = {Journal of Physical Chemistry B},
  title        = {Concentration-Induced Association in a Protein System Caused by a Highly Directional Patch Attraction},
  url          = {http://dx.doi.org/10.1021/acs.jpcb.6b06873},
  volume       = {120},
  year         = {2016},
}