Trapping and charge stabilization in chlorosome containing bacteria: Comparative study on Chloroflexus aurantiacus and Chlorobium limicola

Autor(en): Schmidt, K
Trissl, HW
Stichwörter: biophysical chemistry; CELLS; Chemistry; Chemistry, Physical; dipole moment; energy transfer; ENERGY-TRANSFER; EXCITATION; FAST PHOTOVOLTAGE MEASUREMENTS; fluorescence; GREEN SULFUR BACTERIA; GROWTH; KINETICS; MEMBRANES; photochemistry; PHOTOSYNTHETIC BACTERIA
Erscheinungsdatum: 1996
Herausgeber: VCH PUBLISHERS INC
Journal: BERICHTE DER BUNSEN-GESELLSCHAFT-PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Volumen: 100
Ausgabe: 12
Startseite: 1958
Seitenende: 1961
Zusammenfassung: 
Trapping and charge stabilization in intact cells of Chloroflexus aurantiacus and Chlorobium limicola were studied by means of photovoltage kinetics and fluorescence emission spectra upon excitation in the chlorosome. In Chloroflexus two electrogenic phases with time constants of 100 ps for trapping (P+ H- formation) from the core-complexes and 530 ps for charge stabilization (Q(A) reduction) were found. In Chlorobium there were also two electrogenic phases of 105 ps and 650 ps. The later phase most likely represents the charge stabilization on the iron-sulfur center, F-X. A comparison of stationary fluorescence spectra of both species indicates that the trapping time from the core pigments in Chlorobium is significantly faster than in Chloroflexus. This proves the existence of at least two intermediary accepters between the primary donor (P 840) and F-X in the Chlorobium reaction center. In both species the photovoltage signal in the low excitation limit appeared after a lag phase of 55 to 65 ps, which is ascribed to the energy transfer from the chlorosome to the core pigments.
Beschreibung: 
95th Annual Meeting of the Deutsche-Bunsen-Gesellschaft-fur-Physikalische-Chemie on Primary Processes of Photosynthesis, JENA, GERMANY, MAY 16-18, 1996
ISSN: 00059021
DOI: 10.1002/bbpc.19961001205

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