Authors: Erica Belgio Giorgio Tumino Stefano Santabarbara Giuseppe Zucchelli Robert Jennings
Publish Date: 2011/10/16
Volume: 111, Issue: 1-2, Pages: 53-62
Abstract
The multiexponential fluorescence decay of the CP29 complex in which the apoprotein and pigments were reconstituted in vitro was examined Of the three decay components observed only the two dominant ones with about 3 and 5 ns lifetimes were studied The main question addressed was whether the multicomponent decay was associated with sample optical heterogeneity To this end we examined the optical absorption and fluorescence of the CP29 sample by means of two different and independent experimental strategies This approach was used as the wavelength positions of the absorption/fluorescence spectral forms has recently been shown to be a sensitive indicator of the binding siteinduced porphyrin ring deformation Zucchelli et al Biophys J 932240–2254 2007 and hence of apoprotein conformational changes The data indicate that this CP29 sample is optically homogeneous It is hypothesised that the different lifetimes are explained in terms of multiple detergent/CP29 interactions leading to different quenching states a suggestion that allows for optical homogeneity
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