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Spectroscopy
Volume 24 (2010), Issue 3-4, Pages 257-260
http://dx.doi.org/10.3233/SPE-2010-0402

Gastric ATPase phosphorylation/dephosphorylation monitored by new FTIR-based BIA–ATR biosensors

A. Goldsztein,1,5 S. Babar,1 M. Voué,2,3 J. De Coninck,2 J. Conti,2 J. Marchand-Brynaert,4 S. Devouge,4 F. Homblé,1 and E. Goormaghtigh1

1Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Belgium
2Laboratoire de Physique des Surfaces et des Interfaces, Université de Mons, Mons, Belgium
3Physique des Matériaux et Optique, Université de Mons, Mons, Belgium
4Unité de Chimie Organique et Médicinale, Université Catholique de Louvain, Bâtiment Lavoisier, Louvain-la-Neuve, Belgium
5Center for Structural Biology and Bioinformatics, Laboratory for the Structure and Function of Biological Membranes, Campus Plaine CP206/02, Université Libre de Bruxelles, Bld du Triomphe 2, CP206/02, B1050 Brussels, Belgium

Copyright © 2010 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Biosensors are composite devices suitable for the investigation of receptor–ligand interactions. In this paper we present the specific application to a membrane embedded protein of a new sensor device, so-called BIA–ATR, based on Attenuated Total Reflection–Fourier Transform Infrared (ATR–FTIR) spectroscopy. It consists in a functionalised ATR germanium crystal whose surface has been covalently modified to adsorb a biomembrane. Detection of the ligand–receptor interaction is achieved using FTIR spectroscopy. We report the specific detection of the phosphorylation/dephosphorylation of the H+/K+ gastric ATPase. The H+, K+-ATPase is a particularly large protein entity. This glycosylated protein contains more than 1300 residues and is embedded in a lipid membrane. Yet we demonstrate that the BIA–ATR sensor is capable of monitoring the binding of a single phosphate on such a large protein entity. Furthermore, we also demonstrate the potential of the approach to monitor the kinetics of binding and dissociation of the ligand.