Photophysical properties of Prochlorococcus marinus SS120 divinyl chlorophylls and phycoerythrin in vitro and in vivo

FEBS Letters

Steglich, Claudia²  Lokstein, Heiko¹  Hess, Wolfgang R²  Mullineaux, Conrad W⁴  Teuchner, Klaus³ 

[1] Institut für Biologie/Pflanzenphysiologie, Humboldt-Universität zu Berlin, Unter den Linden 6 (Sitz: Philippstr. 13), D-10099 Berlin, Germany;Institut für Biologie/Genetik, Humboldt-Universität zu Berlin, Chausseestr. 117, D-10115 Berlin, Germany;Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2a, D-12489 Berlin, Germany;Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK

关键词: Excitation energy transfer;    Fluorescence lifetime and quantum yield;    Phycoerythrin;    Spectrofluorimetry;    Synchrotron radiation;    Prochlorococcus;    DV-Chl;    divinyl chlorophyll;    EET;    excitation energy transfer;    PCB;    prochlorophyte chlorophyll b-binding protein;    PE;    phycoerythrin;   

DOI  :  10.1016/S0014-5793(03)00971-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Prochlorococcus marinus SS120 is an ecologically important and biochemically intriguing marine cyanobacterium. In addition to divinyl chlorophylls (DV-Chls) a and b it possesses a particular form of phycoerythrin (PE), but no other phycobilins and therefore no complete phycobilisomes. Here, a spectroscopic characterisation of these DV-Chls and PE is provided. Comparison of fluorescence quantum yields, excited state lifetimes and absorption characteristics indicate similar light-harvesting properties of the DV-Chls as their monovinyl counterparts. PE, which is present only in tiny amounts, was purified and considerably enriched. A phycourobilin to phycoerythrobilin ratio of 3:1 chromophores per (αβ) PE monomer is suggested. The in vitro fluorescence lifetime of PE is 1.74 ns. In vivo time-resolved fluorescence measurements with synchrotron radiation were used to investigate the possible role of PE in light-harvesting. The fluorescence decay time for PE is about 550 ps, indicating an unusually slow excitation energy transfer. The decay time slowed to 1 ns after addition of glycerol to cell cultures. The contribution of PE to total light-harvesting capacity was estimated to be about one (αβ) PE monomer per 330 DV-Chl b molecules. Thus, the capacity of PE to function primarily as a photosynthetic light-harvesting pigment in P. marinus SS120 is low.

【 授权许可】

Unknown