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The carotenoid S-1 state in LH2 complexes from purple bacteria Rhodobacter sphaeroides and Rhodopseudomonas acidophila: S-1 energies, dynamics, and carotenoid radical formation

Polivka, Tomas LU ; Zigmantas, Donatas LU ; Herek, Jennifer LU ; He, Zhi LU ; Pascher, Torbjörn LU ; Pullerits, Tönu LU ; Cogdell, RJ; Frank, HA and Sundström, Villy LU (2002) In The Journal of Physical Chemistry Part B 106(42). p.11016-11025
Abstract
Using near-infrared femtosecond absorption spectroscopy, we have determined the S-1 energies of the carotenoids spheroidene and rhodopin glucoside in LH2 complexes of purple bacteria. The S-1 energies in the LH2 complexes yield values of 13400 +/- 100 cm(-1) for spheroidene and 12550 +/- 150 cm(-1) for rhodopin glucoside, which are very close to the S-1 energies obtained for both carotenoids in solution. The 850 cm(-1) difference between the S-1 energies of these two carotenoids significantly affects the energy transfer pathways within the LH2 complexes. The S-1 energy of spheroidene in the LH2 complex of Rhodobacter (Rb.) sphaeroides is high enough to allow efficient energy transfer from the S, state to bacteriochlorophylls, resulting in... (More)
Using near-infrared femtosecond absorption spectroscopy, we have determined the S-1 energies of the carotenoids spheroidene and rhodopin glucoside in LH2 complexes of purple bacteria. The S-1 energies in the LH2 complexes yield values of 13400 +/- 100 cm(-1) for spheroidene and 12550 +/- 150 cm(-1) for rhodopin glucoside, which are very close to the S-1 energies obtained for both carotenoids in solution. The 850 cm(-1) difference between the S-1 energies of these two carotenoids significantly affects the energy transfer pathways within the LH2 complexes. The S-1 energy of spheroidene in the LH2 complex of Rhodobacter (Rb.) sphaeroides is high enough to allow efficient energy transfer from the S, state to bacteriochlorophylls, resulting in a substantial shortening of the spheroidene S-1 lifetime in the LH2 complex (1.7 ps) compared with the lifetime in solution (8.5 ps). Rhodopin glucoside, which occurs in Rhodopseudomonas (Rps.) acidophila, has an S-1 energy in the LH2 complex too low for efficient S-1-mediated energy transfer and therefore the S-2 state becomes the main energy donor in LH2 complexes containing this carotenoid. In addition, a distinct carotenoid spectral band not observed in solution, was detected at around 960 nm in the LH2 complex of Rb. sphaeroides. This band is assigned to a spheroidene radical cation, which is formed in similar to200 fs and decays within 8 ps. The yield of the spheroidene radical formation is estimated to be in the range of 5-8%. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
106
issue
42
pages
11016 - 11025
publisher
The American Chemical Society
external identifiers
  • wos:000178792200029
  • scopus:0037168308
ISSN
1520-5207
DOI
10.1021/jp025752p
language
English
LU publication?
yes
id
2501a044-d519-480b-841c-087ce0005005 (old id 324717)
date added to LUP
2007-11-09 08:14:31
date last changed
2017-08-06 04:33:41
@article{2501a044-d519-480b-841c-087ce0005005,
  abstract     = {Using near-infrared femtosecond absorption spectroscopy, we have determined the S-1 energies of the carotenoids spheroidene and rhodopin glucoside in LH2 complexes of purple bacteria. The S-1 energies in the LH2 complexes yield values of 13400 +/- 100 cm(-1) for spheroidene and 12550 +/- 150 cm(-1) for rhodopin glucoside, which are very close to the S-1 energies obtained for both carotenoids in solution. The 850 cm(-1) difference between the S-1 energies of these two carotenoids significantly affects the energy transfer pathways within the LH2 complexes. The S-1 energy of spheroidene in the LH2 complex of Rhodobacter (Rb.) sphaeroides is high enough to allow efficient energy transfer from the S, state to bacteriochlorophylls, resulting in a substantial shortening of the spheroidene S-1 lifetime in the LH2 complex (1.7 ps) compared with the lifetime in solution (8.5 ps). Rhodopin glucoside, which occurs in Rhodopseudomonas (Rps.) acidophila, has an S-1 energy in the LH2 complex too low for efficient S-1-mediated energy transfer and therefore the S-2 state becomes the main energy donor in LH2 complexes containing this carotenoid. In addition, a distinct carotenoid spectral band not observed in solution, was detected at around 960 nm in the LH2 complex of Rb. sphaeroides. This band is assigned to a spheroidene radical cation, which is formed in similar to200 fs and decays within 8 ps. The yield of the spheroidene radical formation is estimated to be in the range of 5-8%.},
  author       = {Polivka, Tomas and Zigmantas, Donatas and Herek, Jennifer and He, Zhi and Pascher, Torbjörn and Pullerits, Tönu and Cogdell, RJ and Frank, HA and Sundström, Villy},
  issn         = {1520-5207},
  language     = {eng},
  number       = {42},
  pages        = {11016--11025},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {The carotenoid S-1 state in LH2 complexes from purple bacteria Rhodobacter sphaeroides and Rhodopseudomonas acidophila: S-1 energies, dynamics, and carotenoid radical formation},
  url          = {http://dx.doi.org/10.1021/jp025752p},
  volume       = {106},
  year         = {2002},
}