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A coarse-grained model for flexible (phospho)proteins: Adsorption and bulk properties

Henriques, Joao LU and Skepö, Marie LU (2015) In Food Hydrocolloids 43. p.473-480
Abstract
Protein adsorption is a complex process that it controlled by several different mechanisms, for example: (i) electrostatic interactions between the protein and the surface, and (ii) between adsorbed proteins; (iii) dispersion interactions; (iv) hydration effects; and (v) structural rearrangements of the protein to balance conformational chain entropy with energetics. The aim of this study was to develop a simple model for the adsorption of intrinsically disordered proteins onto surfaces at a mesoscopic level of detail, while retaining protein integrity. Monte Carlo simulations were used in order to study the thermodynamical and structural properties of the flexible phosphoprotein beta-casein, in bulk and adsorbed to hydrophilic silica... (More)
Protein adsorption is a complex process that it controlled by several different mechanisms, for example: (i) electrostatic interactions between the protein and the surface, and (ii) between adsorbed proteins; (iii) dispersion interactions; (iv) hydration effects; and (v) structural rearrangements of the protein to balance conformational chain entropy with energetics. The aim of this study was to develop a simple model for the adsorption of intrinsically disordered proteins onto surfaces at a mesoscopic level of detail, while retaining protein integrity. Monte Carlo simulations were used in order to study the thermodynamical and structural properties of the flexible phosphoprotein beta-casein, in bulk and adsorbed to hydrophilic silica surfaces, in order to evaluate the effect of varying pH, monovalent salt concentration, and degree of serine phosphorylation. Experimental evidence from our previous study, published in this Journal, was used to set up and tune the Hamiltonian of the model. Our simulations show that protein-surface electrostatic interactions are, indeed, not the main driving force behind adsorption under the simulated conditions. Despite its importance, when taken alone, this type of interaction is not enough to promote the adsorption of beta-casein at any salt concentration. Adsorption is only possible through the inclusion of a protein-surface short-ranged attractive interaction potential with a minimum interaction strength of 2.25 k(B)T. This represents the lowest interaction strength required to mimic experimental adsorption results. An equally important finding is that considerable protein net charge fluctuations, due to phosphorylated serine saturation, have a negligible contribution to the free energy of adsorption. (C) 2014 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Flexible proteins, beta-casein, Silica, Monte Carlo, Adsorption
in
Food Hydrocolloids
volume
43
pages
473 - 480
publisher
Elsevier
external identifiers
  • wos:000345683500055
  • scopus:84908339025
ISSN
0268-005X
DOI
10.1016/j.foodhyd.2014.07.002
language
English
LU publication?
yes
id
acb3bc66-822f-4a98-9beb-435d2e24d54c (old id 4962589)
date added to LUP
2015-01-29 11:48:15
date last changed
2017-02-12 03:05:42
@article{acb3bc66-822f-4a98-9beb-435d2e24d54c,
  abstract     = {Protein adsorption is a complex process that it controlled by several different mechanisms, for example: (i) electrostatic interactions between the protein and the surface, and (ii) between adsorbed proteins; (iii) dispersion interactions; (iv) hydration effects; and (v) structural rearrangements of the protein to balance conformational chain entropy with energetics. The aim of this study was to develop a simple model for the adsorption of intrinsically disordered proteins onto surfaces at a mesoscopic level of detail, while retaining protein integrity. Monte Carlo simulations were used in order to study the thermodynamical and structural properties of the flexible phosphoprotein beta-casein, in bulk and adsorbed to hydrophilic silica surfaces, in order to evaluate the effect of varying pH, monovalent salt concentration, and degree of serine phosphorylation. Experimental evidence from our previous study, published in this Journal, was used to set up and tune the Hamiltonian of the model. Our simulations show that protein-surface electrostatic interactions are, indeed, not the main driving force behind adsorption under the simulated conditions. Despite its importance, when taken alone, this type of interaction is not enough to promote the adsorption of beta-casein at any salt concentration. Adsorption is only possible through the inclusion of a protein-surface short-ranged attractive interaction potential with a minimum interaction strength of 2.25 k(B)T. This represents the lowest interaction strength required to mimic experimental adsorption results. An equally important finding is that considerable protein net charge fluctuations, due to phosphorylated serine saturation, have a negligible contribution to the free energy of adsorption. (C) 2014 Elsevier Ltd. All rights reserved.},
  author       = {Henriques, Joao and Skepö, Marie},
  issn         = {0268-005X},
  keyword      = {Flexible proteins,beta-casein,Silica,Monte Carlo,Adsorption},
  language     = {eng},
  pages        = {473--480},
  publisher    = {Elsevier},
  series       = {Food Hydrocolloids},
  title        = {A coarse-grained model for flexible (phospho)proteins: Adsorption and bulk properties},
  url          = {http://dx.doi.org/10.1016/j.foodhyd.2014.07.002},
  volume       = {43},
  year         = {2015},
}