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Lateral Protein-Protein Interactions at Hydrophobic and Charged Surfaces as a Function of pH and Salt Concentration

Hladílková, Jana LU ; Callisen, Thomas H. and Lund, Mikael LU (2016) In The Journal of Physical Chemistry Part B 120(13). p.3303-3310
Abstract

Surface adsorption of Thermomyces lanuginosus lipase (TLL) - a widely used industrial biocatalyst - is studied experimentally and theoretically at different pH and salt concentrations. The maximum achievable surface coverage on a hydrophobic surface occurs around the protein isoelectric point and adsorption is reduced when either increasing or decreasing pH, indicating that electrostatic protein-protein interactions in the adsorbed layer play an important role. Using Metropolis Monte Carlo (MC) simulations, where proteins are coarse grained to the amino acid level, we estimate the protein isoelectric point in the vicinity of charged surfaces as well as the lateral osmotic pressure in the adsorbed monolayer. Good agreement with available... (More)

Surface adsorption of Thermomyces lanuginosus lipase (TLL) - a widely used industrial biocatalyst - is studied experimentally and theoretically at different pH and salt concentrations. The maximum achievable surface coverage on a hydrophobic surface occurs around the protein isoelectric point and adsorption is reduced when either increasing or decreasing pH, indicating that electrostatic protein-protein interactions in the adsorbed layer play an important role. Using Metropolis Monte Carlo (MC) simulations, where proteins are coarse grained to the amino acid level, we estimate the protein isoelectric point in the vicinity of charged surfaces as well as the lateral osmotic pressure in the adsorbed monolayer. Good agreement with available experimental data is achieved and we further make predictions of the protein orientation at hydrophobic and charged surfaces. Finally, we present a perturbation theory for predicting shifts in the protein isoelectric point due to close proximity to charged surfaces. Although this approximate model requires only single protein properties (mean charge and its variance), excellent agreement is found with MC simulations.

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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
120
issue
13
pages
8 pages
publisher
The American Chemical Society
external identifiers
  • scopus:84964328442
  • wos:000373862500004
ISSN
1520-6106
DOI
10.1021/acs.jpcb.5b12225
language
English
LU publication?
yes
id
41ad10b3-95b6-491f-a765-54373a30cebd
date added to LUP
2016-07-26 09:59:45
date last changed
2017-01-01 08:31:11
@article{41ad10b3-95b6-491f-a765-54373a30cebd,
  abstract     = {<p>Surface adsorption of Thermomyces lanuginosus lipase (TLL) - a widely used industrial biocatalyst - is studied experimentally and theoretically at different pH and salt concentrations. The maximum achievable surface coverage on a hydrophobic surface occurs around the protein isoelectric point and adsorption is reduced when either increasing or decreasing pH, indicating that electrostatic protein-protein interactions in the adsorbed layer play an important role. Using Metropolis Monte Carlo (MC) simulations, where proteins are coarse grained to the amino acid level, we estimate the protein isoelectric point in the vicinity of charged surfaces as well as the lateral osmotic pressure in the adsorbed monolayer. Good agreement with available experimental data is achieved and we further make predictions of the protein orientation at hydrophobic and charged surfaces. Finally, we present a perturbation theory for predicting shifts in the protein isoelectric point due to close proximity to charged surfaces. Although this approximate model requires only single protein properties (mean charge and its variance), excellent agreement is found with MC simulations.</p>},
  author       = {Hladílková, Jana and Callisen, Thomas H. and Lund, Mikael},
  issn         = {1520-6106},
  language     = {eng},
  month        = {04},
  number       = {13},
  pages        = {3303--3310},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Lateral Protein-Protein Interactions at Hydrophobic and Charged Surfaces as a Function of pH and Salt Concentration},
  url          = {http://dx.doi.org/10.1021/acs.jpcb.5b12225},
  volume       = {120},
  year         = {2016},
}