TY - JOUR
T1 - Photoprotective mechanisms in the core LH1 antenna pigment-protein complex from the purple photosynthetic bacterium, Rhodospirillum rubrum
AU - Uragami, Chiasa
AU - Sato, Hiroki
AU - Yukihira, Nao
AU - Fujiwara, Masazumi
AU - Kosumi, Daisuke
AU - Gardiner, Alastair T.
AU - Cogdell, Richard J.
AU - Hashimoto, Hideki
N1 - Funding Information:
HH thanks JSPS KAKENHI, Grant-in-Aids for Basic Research (B) (No. 16H04181) for financial support. HH and DK are grateful to JSPS KAKENHI, Scientific Research on Innovative Areas ?Innovations for Light-Energy Conversion (I4LEC)? (No.17H06433, No. 17H0637 & No. 18H05173) by JSPS for financial support. R.J.C. and A.T.G. gratefully acknowledge support from the Photosynthetic Antenna Research Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC 0001035.
Funding Information:
HH thanks JSPS KAKENHI , Grant-in-Aids for Basic Research (B) (No. 16H04181 ) for financial support. HH and DK are grateful to JSPS KAKENHI , Scientific Research on Innovative Areas “Innovations for Light-Energy Conversion (I 4 LEC)” (No.17H06433, No. 17H0637 & No. 18H05173) by JSPS for financial support. R.J.C. and A.T.G. gratefully acknowledge support from the Photosynthetic Antenna Research Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC 0001035 .
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/9/1
Y1 - 2020/9/1
N2 - Time-resolved absorption spectra from the femtoscecond to sub-millisecond time regimes were recorded in order to eluciate the photoprotective mechanisms of carotenoid (spirilloxanthin) in core LH1 light-harvesting pigment-protein complexes from a purple photosynthetic bacterium, Rhodospirillum (Rsp.) rubrum. Carotenoids can prevent the production of singlet oxygen by rapidly quenching the Bchl a triplet state. Through this triplet-triplet energy-transfer reaction the carotenoid is believed to protect the biological system from exposure to excess light. We set out to investigate this paricular function in the purple bacterium, Rsp. rubrum strain S1. We also investigated Rsp. rubrum strain G9+, which is the carotenoidless mutant of Rsp. rubrum, to make sure that the carotenoid is truly playing this important role. As a result, we could demonstrate that strain S1 realizes nearly 100% excitation energy transfer from triplet Bchl a to carotenoid. In addition, we found another major excited state deactivation channel of carotenoids, which takes away excess energy directly from the singlet excited state of Bchl a and so prevents the production of triplet excited Bchl a.
AB - Time-resolved absorption spectra from the femtoscecond to sub-millisecond time regimes were recorded in order to eluciate the photoprotective mechanisms of carotenoid (spirilloxanthin) in core LH1 light-harvesting pigment-protein complexes from a purple photosynthetic bacterium, Rhodospirillum (Rsp.) rubrum. Carotenoids can prevent the production of singlet oxygen by rapidly quenching the Bchl a triplet state. Through this triplet-triplet energy-transfer reaction the carotenoid is believed to protect the biological system from exposure to excess light. We set out to investigate this paricular function in the purple bacterium, Rsp. rubrum strain S1. We also investigated Rsp. rubrum strain G9+, which is the carotenoidless mutant of Rsp. rubrum, to make sure that the carotenoid is truly playing this important role. As a result, we could demonstrate that strain S1 realizes nearly 100% excitation energy transfer from triplet Bchl a to carotenoid. In addition, we found another major excited state deactivation channel of carotenoids, which takes away excess energy directly from the singlet excited state of Bchl a and so prevents the production of triplet excited Bchl a.
KW - Carotenoid
KW - LH1 pigment-protein antenna complex
KW - Photoprotective function
KW - Purple photosynthetic bacteria
KW - Time-resolved absorption spectroscopy
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U2 - 10.1016/j.jphotochem.2020.112628
DO - 10.1016/j.jphotochem.2020.112628
M3 - Article
AN - SCOPUS:85086455957
VL - 400
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
SN - 1010-6030
M1 - 112628
ER -