title: Reconstituted CP29: multicomponent fluorescence decay from an optically homogeneous sample.
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 site-induced porphyrin ring deformation (Zucchelli et al.  Biophys J 93:2240-2254, 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.
authors: CNR-Istituto di Biofisica, Sede di Milano, Via G. Celoria 26, 20133, Milan, Italy.
authors: Erica
authors: E
authors: Belgio
authors: Giorgio
authors: G
authors: Tumino
authors: Stefano
authors: S
authors: Santabarbara
authors: Giuseppe
authors: G
authors: Zucchelli
authors: Robert
authors: R
authors: Jennings
mesh_terms: D001059:Apoproteins / Q000737:chemistry* / Q000378:metabolism; D016227:Benzoquinones; D001665:Binding Sites; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism; D010860:Pigments, Biological / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins; D013050:Spectrometry, Fluorescence
chemical_list: D001059:Apoproteins; D016227:Benzoquinones; C069660:CP29 light harvesting complex; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D010860:Pigments, Biological; D011994:Recombinant Proteins; C004532:quinone