title: Quantitative detection of conformational transitions in a calcium sensor protein by surface plasmon resonance.
abstract: We determined the conditions under which surface plasmon resonance can be used to monitor at real-time the Ca(2+)-induced conformational transitions of the sensor protein recoverin immobilized over a sensor chip. The equilibrium and the kinetics of conformational transitions were detected and quantified over a physiological range of Ca(2+) and protein concentrations similar to those found within cells. Structural analysis suggests that the detection principle reflects changes in the hydrodynamic properties of the protein and is not due to a mass effect. The phenomenon appears to be related to changes in the refractive index at the metal/dielectric interface.
authors.affiliation: Institute of Biology and Environmental Sciences, Biochemistry Group, University of Oldenburg, D-26111 Oldenburg, Germany. daniele.dellorco@uni-oldenburg.de
authors.forename: Daniele
authors.initials: D
authors.lastname: Dell'Orco
authors.forename: Michael
authors.initials: M
authors.lastname: Müller
authors.forename: Karl-Wilhelm
authors.initials: KW
authors.lastname: Koch
mesh_terms: D052139:Intracellular Calcium-Sensing Proteins / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D052139:Intracellular Calcium-Sensing Proteins