title: Fluorescence-excitation and emission spectra from LH2 antenna complexes of Rhodopseudomonas acidophila as a function of the sample preparation conditions.
abstract: The high sensitivity of optical spectra of pigment-protein complexes to temperature and pressure is well known. In the present study, we have demonstrated the significant influence of the environments commonly used in bulk and single-molecule spectroscopic studies at low temperatures on the LH2 photosynthetic antenna complex from Rhodopseudomonas acidophila. A transfer of this LH2 complex from a bulk-buffer solution into a spin-coated polymer film results in a 189 cm(-1) blue shift of the B850 excitonic absorption band at 5 K. Within the molecular exciton model, the origin of this shift could be disentangled into three parts, namely to an increase of the local site energies, a contraction of the exciton band, and a decrease of the displacement energy.
authors.affiliation: Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth , 95440 Bayreuth, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kunz
authors.forename: Kõu
authors.initials: K
authors.lastname: Timpmann
authors.forename: June
authors.initials: J
authors.lastname: Southall
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cogdell
authors.forename: Jürgen
authors.initials: J
authors.lastname: Köhler
authors.forename: Arvi
authors.initials: A
authors.lastname: Freiberg
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D012241:Rhodopseudomonas / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes