Exciton level structure and dynamics in the CP47 antenna complex of photosystem II

Journal Article · Thu Aug 04 04:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100082a050· OSTI ID:7191420

Chang, H C; Jankowiak, R; Small, G J ^[1]; Yocum, C F ^[2]; Picorel, R ^[3]; Alfonso, M ^[4]; Seibert, M ^[5]

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1. Ames Lab.-USDOE, IA (United States) Iowa State Univ., Ames, IA (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States)
3. CSIC, Zaragoza (Spain) National Renewable Energy Lab., Golden, CO (United States)
4. CSIC, Zaragoza (Spain)
5. National Renewable Energy Lab., Golden, CO (United States)

Persistent nonphotochemical and population bottleneck hole-burning results obtained as a function of burn wavelength are reported for the CP47 proximal antenna protein complex of photosystem II. Attention is focused on the lower energy chlorophyll a Q[sub y] states. Results are presented for the CP47 complex from two preparations. The Chl a content per CP47 complex was determined, spectroscopically, to be 14 [+-] 2. On the basis of the analysis of the hole spectra and the 4.2 K static fluorescence spectrum, the lowest energy state of CP47 lies at 690 nm (fluorescence origin at 691 nm). The width of the weak 690-nm absorption band from inhomogeneous broadening is 100 cm[sup [minus]1]. The linear electron-phonon coupling of the 690-nm state is weak with a Huang-Rhys factor (S) of about 0.2 and a mean phonon frequency ([Omega][sub m]) of 120 cm[sup [minus]1], which explains why the Stokes shift (2S[Omega][sub m]) is so small. The 690-nm state is found to be excitonically correlated with a hitherto unobserved state at 687 nm. However, the combined absorption intensity of the 690- and 687-nm states was determined to be equivalent to only 1 Chl a molecule. Results are presented which illustrate that these two states are fragile (i.e., their associated chlorophyll a molecules are disrupted). Thus, it is possible that the correct number of Chl a molecules is 2, not 1. 53 refs., 9 figs., 1 tab.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 7191420
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:31; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

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ABSORPTION SPECTROSCOPY
BEETS
CARBOXYLIC ACIDS
CHLOROPHYLL
COMPLEXES
COUPLING
DYNAMICS
ELECTRON-PHONON COUPLING
ENERGY TRANSFER
EXCITONS
FLUORESCENCE
FOOD
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LASERS
LUMINESCENCE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MECHANICS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOSYNTHETIC REACTION CENTERS
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
PROTEINS
QUASI PARTICLES
SPECTROSCOPY
SUGAR BEETS
VEGETABLES