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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1995 Dec 19;92(26):12333–12337. doi: 10.1073/pnas.92.26.12333

Temporally and spectrally resolved subpicosecond energy transfer within the peripheral antenna complex (LH2) and from LH2 to the core antenna complex in photosynthetic purple bacteria.

S Hess 1, M Chachisvilis 1, K Timpmann 1, M R Jones 1, G J Fowler 1, C N Hunter 1, V Sundström 1
PMCID: PMC40351  PMID: 11607622

Abstract

We report studies of energy transfer from the 800-nm absorbing pigment (B800) to the 850-nm absorbing pigment (B850) of the LH2 peripheral antenna complex and from LH2 to the core antenna complex (LH1) in Rhodobacter (Rb.) sphaeroides. The B800 to B850 process was studied in membranes from a LH2-reaction center (no LH1) mutant of Rb. sphaeroides and the LH2 to LH1 transfer was studied in both the wild-type species and in LH2 mutants with blue-shifted B850. The measurements were performed by using approximately 100-fs pulses to probe the formation of acceptor excitations in a two-color pump-probe measurement. Our experiments reveal a B800 to B850 transfer time of approximately 0.7 ps at 296 K and energy transfer from LH2 to LH1 is characterized by a time constant of approximately 3 ps at 296 K and approximately 5 ps at 77 K. In the blue-shifted B850 mutants, the transfer time from B850 to LH1 becomes gradually longer with increasing blue-shift of the B850 band as a result of the decreasing spectral overlap between the antennae. The results have been used to produce a model for the association between the ring-like structures that are characteristic of both the LH2 and LH1 antennae.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Beekman L. M., van Mourik F., Jones M. R., Visser H. M., Hunter C. N., van Grondelle R. Trapping kinetics in mutants of the photosynthetic purple bacterium Rhodobacter sphaeroides: influence of the charge separation rate and consequences for the rate-limiting step in the light-harvesting process. Biochemistry. 1994 Mar 22;33(11):3143–3147. doi: 10.1021/bi00177a001. [DOI] [PubMed] [Google Scholar]
  2. Fowler G. J., Visschers R. W., Grief G. G., van Grondelle R., Hunter C. N. Genetically modified photosynthetic antenna complexes with blueshifted absorbance bands. Nature. 1992 Feb 27;355(6363):848–850. doi: 10.1038/355848a0. [DOI] [PubMed] [Google Scholar]
  3. Hess S., Visscher K. J., Pullerits T., Sundström V., Fowler G. J., Hunter C. N. Enhanced rates of subpicosecond energy transfer in blue-shifted light harvesting LH2 mutants of Rhodobacter sphaeroides. Biochemistry. 1994 Jul 12;33(27):8300–8305. doi: 10.1021/bi00193a017. [DOI] [PubMed] [Google Scholar]
  4. Hess S., Visscher K., Ulander J., Pullerits T., Jones M. R., Hunter C. N., Sundström V. Direct energy transfer from the peripheral LH2 antenna to the reaction center in a mutant of Rhodobacter sphaeroides that lacks the core LH1 antenna. Biochemistry. 1993 Oct 5;32(39):10314–10322. doi: 10.1021/bi00090a006. [DOI] [PubMed] [Google Scholar]
  5. Karrasch S., Bullough P. A., Ghosh R. The 8.5 A projection map of the light-harvesting complex I from Rhodospirillum rubrum reveals a ring composed of 16 subunits. EMBO J. 1995 Feb 15;14(4):631–638. doi: 10.1002/j.1460-2075.1995.tb07041.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Lipkind G. M., Fozzard H. A. A structural model of the tetrodotoxin and saxitoxin binding site of the Na+ channel. Biophys J. 1994 Jan;66(1):1–13. doi: 10.1016/S0006-3495(94)80746-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Shreve A. P., Trautman J. K., Frank H. A., Owens T. G., Albrecht A. C. Femtosecond energy-transfer processes in the B800-850 light-harvesting complex of Rhodobacter sphaeroides 2.4.1. Biochim Biophys Acta. 1991 Jun 17;1058(2):280–288. doi: 10.1016/s0005-2728(05)80248-8. [DOI] [PubMed] [Google Scholar]
  8. Zhang F. G., van Grondelle R., Sundström V. Pathways of energy flow through the light-harvesting antenna of the photosynthetic purple bacterium rhodobacter sphaeroides. Biophys J. 1992 Apr;61(4):911–920. doi: 10.1016/S0006-3495(92)81898-2. [DOI] [PMC free article] [PubMed] [Google Scholar]

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