Laboratoire Léon Brillouin

UMR12 CEA-CNRS, Bât. 563 CEA Saclay

91191 Gif sur Yvette Cedex, France

+33-169085241 llb-sec@cea.fr

BD diffusons les neutrons

A neutron reflection study of adsorbed deuterated myoglobin layers on hydrophobic surfaces  
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Nicolas Brouette, Giovanna Fragneto, Fabrice Cousin, Martine Moulin, Michael Haertlein, Michele Sferrazza

The structure of adsorbed globular protein layers on hydrophobic surfaces is elucidated in detail by combining the use of a fully deuterated protein, myoglobin, and the neutron reflectivity technique. The hydrophobic surfaces consist of grafted self-assembled monolayer of octadecyltrichlorosilane (OTS) and polystyrene (PS) layer on silicon substrates. Different protein concentrations ranging from 1 mg/ml to 0.01 mg/ml are used. On the OTS surface and for low protein concentration, the adsorbed protein layer consists of a dense layer of thickness around 13 Å indicating that proteins are denaturated when adsorbed on the hydrophobic interface – myoglobin being a globular protein with an average diameter of about 40 Å. At high protein concentration, an additional layer is observed on the top of this first denaturated layer. The thickness of this layer corresponds roughly to the dimensions of the myoglobin suggesting that additional proteins in their bulk conformation are adsorbed on the top. In the case of PS, the protein is significantly less flattened at the interface, PS being a less hydrophobic surface.

http://dx.doi.org/10.1016/j.jcis.2012.09 ...

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