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Interactions and conformations of alpha-helical human apolipoprotein CI on hydrophilic and on hydrophobic substrates

Campos, José LU ; Mas-Oliva, J and Castillo, R (2004) In The Journal of Physical Chemistry Part B 108(52). p.20442-20450
Abstract
Interactions between amphiphilic alpha-helical human apolipoprotein CI (APO CI) adsorbed on hydrophilic and on hydrophobic surfaces were studied using an interferometric surface force apparatus in an effort to understand the surface conformation and the binding activity of this protein. We used mica as the hydrophilic substrate and polymerized octadecyltriethoxysilane (OTE)-covered mica as the hydrophobic substrate. The OTE monolayer and the OTE Langmuir-Blodgett film were studied using Brewster angle microscopy and atomic force microscopy, respectively. We found that interaction forces between layers of APO CI adsorbed on hydrophilic and on hydrophobic surfaces are mainly due to electrostatic double-layer forces at large surface distances... (More)
Interactions between amphiphilic alpha-helical human apolipoprotein CI (APO CI) adsorbed on hydrophilic and on hydrophobic surfaces were studied using an interferometric surface force apparatus in an effort to understand the surface conformation and the binding activity of this protein. We used mica as the hydrophilic substrate and polymerized octadecyltriethoxysilane (OTE)-covered mica as the hydrophobic substrate. The OTE monolayer and the OTE Langmuir-Blodgett film were studied using Brewster angle microscopy and atomic force microscopy, respectively. We found that interaction forces between layers of APO CI adsorbed on hydrophilic and on hydrophobic surfaces are mainly due to electrostatic double-layer forces at large surface distances and to steric repulsive forces at small distances. In some cases, no force was measured prior to finding a steric wall, suggesting that a complete neutralization of the surface charge was achieved by the protein adsorption. Protein layer thickness values allow us to give an image of the organization and conformation of the APO CI protein on surfaces. The adhesion obtained in both kinds of surfaces indicates that the interaction between the hydrophobic sides of the APO CI proteins is stronger than that between the hydrophilic sides of the protein. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
108
issue
52
pages
20442 - 20450
publisher
The American Chemical Society
external identifiers
  • wos:000225925100074
  • scopus:11344289669
ISSN
1520-5207
DOI
10.1021/jp048305d
language
English
LU publication?
no
id
5917ffaa-3e86-4a07-88be-207c17deecf1 (old id 258366)
date added to LUP
2007-10-17 14:50:34
date last changed
2017-01-01 06:44:36
@article{5917ffaa-3e86-4a07-88be-207c17deecf1,
  abstract     = {Interactions between amphiphilic alpha-helical human apolipoprotein CI (APO CI) adsorbed on hydrophilic and on hydrophobic surfaces were studied using an interferometric surface force apparatus in an effort to understand the surface conformation and the binding activity of this protein. We used mica as the hydrophilic substrate and polymerized octadecyltriethoxysilane (OTE)-covered mica as the hydrophobic substrate. The OTE monolayer and the OTE Langmuir-Blodgett film were studied using Brewster angle microscopy and atomic force microscopy, respectively. We found that interaction forces between layers of APO CI adsorbed on hydrophilic and on hydrophobic surfaces are mainly due to electrostatic double-layer forces at large surface distances and to steric repulsive forces at small distances. In some cases, no force was measured prior to finding a steric wall, suggesting that a complete neutralization of the surface charge was achieved by the protein adsorption. Protein layer thickness values allow us to give an image of the organization and conformation of the APO CI protein on surfaces. The adhesion obtained in both kinds of surfaces indicates that the interaction between the hydrophobic sides of the APO CI proteins is stronger than that between the hydrophilic sides of the protein.},
  author       = {Campos, José and Mas-Oliva, J and Castillo, R},
  issn         = {1520-5207},
  language     = {eng},
  number       = {52},
  pages        = {20442--20450},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Interactions and conformations of alpha-helical human apolipoprotein CI on hydrophilic and on hydrophobic substrates},
  url          = {http://dx.doi.org/10.1021/jp048305d},
  volume       = {108},
  year         = {2004},
}