title: Multi-Level, Multi Time-Scale Fluorescence Intermittency of Photosynthetic LH2 Complexes: A Precursor of Non-Photochemical Quenching?
abstract: The light harvesting complex LH2 is a chromoprotein that is an ideal system for studying protein dynamics via the spectral fluctuations of the emission of its intrinsic chromophores. We have immobilized these complexes in a polymer film and studied the fluctuations of the fluorescence intensity from individual complexes over 9 orders of magnitude in time. Combining time-tagged detection of single photons with a change-point analysis has allowed the unambigeous identification of the various intensity levels due to the huge statistical basis of the data set. We propose that the observed intensity level fluctuations reflect conformational changes of the protein backbone that might be a precursor of the mechanism from which nonphotochemical quenching of higher plants has evolved.
authors.affiliation: Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth , 95447 Bayreuth, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Schörner
authors.affiliation: Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth , 95447 Bayreuth, Germany.
authors.forename: Sebastian Reinhardt
authors.initials: SR
authors.lastname: Beyer
authors.affiliation: Institute of Molecular, Cell & Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow , Glasgow G12 8QQ, United Kingdom.
authors.forename: June
authors.initials: J
authors.lastname: Southall
authors.affiliation: Institute of Molecular, Cell & Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow , Glasgow G12 8QQ, United Kingdom.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cogdell
authors.affiliation: Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth , 95447 Bayreuth, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Köhler
mesh_terms: D000465:Algorithms; D005453:Fluorescence; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D055668:Photochemical Processes; D012241:Rhodopseudomonas / Q000737:chemistry; D013997:Time Factors
chemical_list: D045342:Light-Harvesting Protein Complexes