TY - JOUR
T1 - Excitation energy transfer and trapping dynamics in the core complex of the filamentous photosynthetic bacterium Roseiflexus castenholzii
AU - Xin, Yueyong
AU - Pan, Jie
AU - Collins, Aaron M.
AU - Lin, Su
AU - Blankenship, Robert E.
N1 - Funding Information:
Acknowledgments We thank Prof. Neal Woodbury from Arizona State University and Richard Loomis from Washington University in St. Louis for helpful discussions. The financial support is in part from DOE grant to REB (DE-FG02-10ER15902), and NSF grant to JP (MCB0642260).
PY - 2012/3
Y1 - 2012/3
N2 - The light-harvesting core complex of the thermophilic filamentous anoxygenic phototrophic bacterium Roseiflexus castenholzii is intrinsic to the cytoplasmic membrane and intimately bound to the reaction center (RC). Using ultrafast transient absorption and time-resolved fluorescence spectroscopy with selective excitation, energy transfer, and trapping dynamics in the core complex have been investigated at room temperature in both open and closed RCs. Results presented in this report revealed that the excited energy transfer from the BChl 800 to the BChl 880 band of the antenna takes about 2 ps independent of the trapping by the RC. The time constants for excitation quenching in the core antenna BChl 880 by open and closed RCs were found to be 60 and 210 ps, respectively. Assuming that the light harvesting complex is generally similar to LH1 of purple bacteria, the possible structural and functional aspects of this unique antenna complex are discussed. The results show that the core complex of Roseiflexus castenholzii contains characteristics of both purple bacteria and Chloroflexus aurantiacus.
AB - The light-harvesting core complex of the thermophilic filamentous anoxygenic phototrophic bacterium Roseiflexus castenholzii is intrinsic to the cytoplasmic membrane and intimately bound to the reaction center (RC). Using ultrafast transient absorption and time-resolved fluorescence spectroscopy with selective excitation, energy transfer, and trapping dynamics in the core complex have been investigated at room temperature in both open and closed RCs. Results presented in this report revealed that the excited energy transfer from the BChl 800 to the BChl 880 band of the antenna takes about 2 ps independent of the trapping by the RC. The time constants for excitation quenching in the core antenna BChl 880 by open and closed RCs were found to be 60 and 210 ps, respectively. Assuming that the light harvesting complex is generally similar to LH1 of purple bacteria, the possible structural and functional aspects of this unique antenna complex are discussed. The results show that the core complex of Roseiflexus castenholzii contains characteristics of both purple bacteria and Chloroflexus aurantiacus.
KW - Core complex
KW - Excitation energy transfer
KW - Filamentous anoxygenic photosynthetic bacterium
KW - Roseiflexus castenholzii
KW - Trapping
KW - Ultrafast spectroscopy
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U2 - 10.1007/s11120-011-9669-6
DO - 10.1007/s11120-011-9669-6
M3 - Article
C2 - 21792612
AN - SCOPUS:84858158946
SN - 0166-8595
VL - 111
SP - 149
EP - 156
JO - Photosynthesis research
JF - Photosynthesis research
IS - 1-2
ER -