title: Orientations between Red Antenna States of Photosystem I Monomers from Thermosynechococcus elongatus Revealed by Single-Molecule Spectroscopy.
abstract: Single-molecule spectroscopy at low temperature was used to study the spectral properties, heterogeneities, and spectral dynamics of the chlorophyll a (Chl a) molecules responsible for the fluorescence emission of photosystem I monomers (PS I-M) from the cyanobacterium Thermosynechococcus elongatus. The fluorescence spectra of single PS I-M are dominated by several red-shifted chlorophyll a molecules named C708 and C719. The emission spectra show broad spectral distributions and several zero-phonon lines (ZPLs). Compared with the spectra of the single PS I trimers, some contributions are missing due to the lower number of C719 Chl's in monomers. Polarization-dependent measurements show an almost perpendicular orientation between the emitters corresponding to C708 and C719. These contributions can be assigned to chlorophyll dimers B18B19, B31B32, and B32B33.
authors.affiliation: IPTC and Lisa+ Center, University of Tübingen , D-72076 Tübingen, Germany.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Skandary
authors.affiliation: IPTC and Lisa+ Center, University of Tübingen , D-72076 Tübingen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Konrad
authors.affiliation: IPTC and Lisa+ Center, University of Tübingen , D-72076 Tübingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hussels
authors.affiliation: IPTC and Lisa+ Center, University of Tübingen , D-72076 Tübingen, Germany.
authors.forename: Alfred J
authors.initials: AJ
authors.lastname: Meixner
authors.affiliation: IPTC and Lisa+ Center, University of Tübingen , D-72076 Tübingen, Germany.|Zurich University of Applied Science (ZHAW) , CH-8401 Winterthur, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Brecht
mesh_terms: D045331:Photosystem I Protein Complex / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D046940:Synechococcus / Q000201:enzymology*; D013696:Temperature; D013997:Time Factors
chemical_list: D045331:Photosystem I Protein Complex