U.S. Department of Energy Office of Scientific and Technical Information
Carotenoid-to-Bacteriochlorophyll Energy Transfer in the LH1–RC Core Complex of a Bacteriochlorophyll b Containing Purple Photosynthetic Bacterium Blastochloris viridis
Journal Article·· Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
Carotenoid-to-bacteriochlorophyll energy transfer has been widely investigated in bacteriochlorophyll (BChl) $$a$$-containing light harvesting complexes. Blastochloris viridis utilizes BChl b, whose absorption spectrum is more red-shifted than that of BChl α. This has implications on the efficiency and pathways of carotenoid-to-BChl energy transfer in this organism. The carotenoids that comprise the light-harvesting reaction center core complex (LH1–RC) of B. viridis are 1,2-dihydroneurosporene and 1,2-dihydrolycopene, which are derivatives of carotenoids found in the light harvesting complexes of several BChl α-containing purple photosynthetic bacteria. Steady-state and ultrafast time-resolved optical spectroscopic measurements were performed on the LH1–RC complex of B. at room and cryogenic temperatures. The overall efficiency of carotenoid-to-bacteriochlorophyll energy transfer obtained from steady-state absorption and fluorescence measurements were determined to be ~27% and ~36% for 1,2-dihydroneurosporene and 1,2-dihydrolycopene, respectively. These results were combined with global fitting and target analyses of the transient absorption data to elucidate the energetic pathways by which the carotenoids decay and transfer excitation energy to BChl b. 1,2-Dihydrolycopene transfers energy to BChl b via the S2 → Qx channel with $$k$$ET2 = (500 fs)-1 while 1,2-dihydroneurosporene transfers energy via S1→ Qy ($$k$$ET1 = (84 ps)-1) and S2 → Qx ($$k$$ET2 = (2.2 ps)-1) channels.
Magdaong, Nikki Cecil M., et al. "Carotenoid-to-Bacteriochlorophyll Energy Transfer in the LH1–RC Core Complex of a Bacteriochlorophyll <em>b</em> Containing Purple Photosynthetic Bacterium <em>Blastochloris viridis</em>." Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, vol. 120, no. 23, May. 2016. https://doi.org/10.1021/acs.jpcb.6b04307
Magdaong, Nikki Cecil M., Niedzwiedzki, Dariusz M., Goodson, Carrie, & Blankenship, Robert E. (2016). Carotenoid-to-Bacteriochlorophyll Energy Transfer in the LH1–RC Core Complex of a Bacteriochlorophyll <em>b</em> Containing Purple Photosynthetic Bacterium <em>Blastochloris viridis</em>. Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, 120(23). https://doi.org/10.1021/acs.jpcb.6b04307
Magdaong, Nikki Cecil M., Niedzwiedzki, Dariusz M., Goodson, Carrie, et al., "Carotenoid-to-Bacteriochlorophyll Energy Transfer in the LH1–RC Core Complex of a Bacteriochlorophyll <em>b</em> Containing Purple Photosynthetic Bacterium <em>Blastochloris viridis</em>," Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry 120, no. 23 (2016), https://doi.org/10.1021/acs.jpcb.6b04307
@article{osti_1387879,
author = {Magdaong, Nikki Cecil M. and Niedzwiedzki, Dariusz M. and Goodson, Carrie and Blankenship, Robert E.},
title = {Carotenoid-to-Bacteriochlorophyll Energy Transfer in the LH1–RC Core Complex of a Bacteriochlorophyll <em>b</em> Containing Purple Photosynthetic Bacterium <em>Blastochloris viridis</em>},
annote = {Carotenoid-to-bacteriochlorophyll energy transfer has been widely investigated in bacteriochlorophyll (BChl) $a$-containing light harvesting complexes. Blastochloris viridis utilizes BChl b, whose absorption spectrum is more red-shifted than that of BChl α. This has implications on the efficiency and pathways of carotenoid-to-BChl energy transfer in this organism. The carotenoids that comprise the light-harvesting reaction center core complex (LH1–RC) of B. viridis are 1,2-dihydroneurosporene and 1,2-dihydrolycopene, which are derivatives of carotenoids found in the light harvesting complexes of several BChl α-containing purple photosynthetic bacteria. Steady-state and ultrafast time-resolved optical spectroscopic measurements were performed on the LH1–RC complex of B. at room and cryogenic temperatures. The overall efficiency of carotenoid-to-bacteriochlorophyll energy transfer obtained from steady-state absorption and fluorescence measurements were determined to be ~27% and ~36% for 1,2-dihydroneurosporene and 1,2-dihydrolycopene, respectively. These results were combined with global fitting and target analyses of the transient absorption data to elucidate the energetic pathways by which the carotenoids decay and transfer excitation energy to BChl b. 1,2-Dihydrolycopene transfers energy to BChl b via the S2 → Qx channel with $k$ET2 = (500 fs)-1 while 1,2-dihydroneurosporene transfers energy via S1→ Qy ($k$ET1 = (84 ps)-1) and S2 → Qx ($k$ET2 = (2.2 ps)-1) channels.},
doi = {10.1021/acs.jpcb.6b04307},
url = {https://www.osti.gov/biblio/1387879},
journal = {Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry},
issn = {ISSN 1520-6106},
number = {23},
volume = {120},
place = {United States},
publisher = {American Chemical Society},
year = {2016},
month = {05}}
Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC); Washington Univ., St. Louis, MO (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
SC0001035
OSTI ID:
1387879
Journal Information:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry Journal Issue: 23 Vol. 120; ISSN 1520-6106