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Weak Self-Interactions of Globular Proteins Studied by Small-Angle X-ray Scattering and Structure-Based Modeling.

Kaieda, Shuji LU ; Lund, Mikael LU ; Plivelic, Tomás LU and Halle, Bertil LU (2014) In The Journal of Physical Chemistry Part B 118(34). p.10111-10119
Abstract
We investigate protein-protein interactions in solution by small-angle X-ray scattering (SAXS) and theoretical modeling. The structure factor for solutions of bovine pancreatic trypsin inhibitor (BPTI), myoglobin (Mb), and intestinal fatty acid-binding protein (IFABP) is determined from SAXS measurements at multiple concentrations, from Monte Carlo simulations with a coarse-grained structure-based interaction model, and from analytic approximate solutions of two idealized colloidal interaction models without adjustable parameters. By combining these approaches, we find that the structure factor is essentially determined by hard-core and screened electrostatic interactions. Other soft short-ranged interactions (van der Waals and... (More)
We investigate protein-protein interactions in solution by small-angle X-ray scattering (SAXS) and theoretical modeling. The structure factor for solutions of bovine pancreatic trypsin inhibitor (BPTI), myoglobin (Mb), and intestinal fatty acid-binding protein (IFABP) is determined from SAXS measurements at multiple concentrations, from Monte Carlo simulations with a coarse-grained structure-based interaction model, and from analytic approximate solutions of two idealized colloidal interaction models without adjustable parameters. By combining these approaches, we find that the structure factor is essentially determined by hard-core and screened electrostatic interactions. Other soft short-ranged interactions (van der Waals and solvation-related) are either individually insignificant or tend to cancel out. The structure factor is also not significantly affected by charge fluctuations. For Mb and IFABP, with a small net charge and relatively symmetric charge distribution, the structure factor is well described by a hard-sphere model. For BPTI, with a larger net charge, screened electrostatic repulsion is also important, but the asymmetry of the charge distribution reduces the repulsion from that predicted by a charged hard-sphere model with the same net charge. Such charge asymmetry may also amplify the effect of shape asymmetry on the protein-protein potential of mean force. (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
118
issue
34
pages
10111 - 10119
publisher
The American Chemical Society
external identifiers
  • pmid:25117055
  • wos:000341121800011
  • scopus:84906842224
ISSN
1520-5207
DOI
10.1021/jp505809v
language
English
LU publication?
yes
id
d197cf03-ef59-41b9-bc6f-b3b3adc53deb (old id 4614827)
date added to LUP
2014-09-12 16:41:32
date last changed
2017-01-01 03:20:24
@article{d197cf03-ef59-41b9-bc6f-b3b3adc53deb,
  abstract     = {We investigate protein-protein interactions in solution by small-angle X-ray scattering (SAXS) and theoretical modeling. The structure factor for solutions of bovine pancreatic trypsin inhibitor (BPTI), myoglobin (Mb), and intestinal fatty acid-binding protein (IFABP) is determined from SAXS measurements at multiple concentrations, from Monte Carlo simulations with a coarse-grained structure-based interaction model, and from analytic approximate solutions of two idealized colloidal interaction models without adjustable parameters. By combining these approaches, we find that the structure factor is essentially determined by hard-core and screened electrostatic interactions. Other soft short-ranged interactions (van der Waals and solvation-related) are either individually insignificant or tend to cancel out. The structure factor is also not significantly affected by charge fluctuations. For Mb and IFABP, with a small net charge and relatively symmetric charge distribution, the structure factor is well described by a hard-sphere model. For BPTI, with a larger net charge, screened electrostatic repulsion is also important, but the asymmetry of the charge distribution reduces the repulsion from that predicted by a charged hard-sphere model with the same net charge. Such charge asymmetry may also amplify the effect of shape asymmetry on the protein-protein potential of mean force.},
  author       = {Kaieda, Shuji and Lund, Mikael and Plivelic, Tomás and Halle, Bertil},
  issn         = {1520-5207},
  language     = {eng},
  number       = {34},
  pages        = {10111--10119},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Weak Self-Interactions of Globular Proteins Studied by Small-Angle X-ray Scattering and Structure-Based Modeling.},
  url          = {http://dx.doi.org/10.1021/jp505809v},
  volume       = {118},
  year         = {2014},
}