Primary charge separation in mutant reaction centers of Rhodobacter capsulatus

Journal Article · Thu Dec 16 00:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100152a024· OSTI ID:5067857

Jia, Y; Du, M; Fleming, G R ^[1]; DiMagno, T J ^[2]; Chan, C K; Schiffer, M ^[3]; Wang, Z; Norris, J R; Popov, M S ^[4]; Hanson, D K ^[5]

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1. Univ. of Chicago, IL (United States)
2. California Inst. of Technology, CA (United States)
3. Argonne National Lab., IL (United States)
4. Univ. of Chicago, IL (United States) Argonne National Lab., IL (United States)
5. National Inst. of Health, Bethesda, MD (United States)

Excited-state decays of the special pair of Rhodobacter capsulatus and 10 mutants as a function of temperature are presented. The mutations are at the symmetry-related sites L181 and M208. All the decays are nonexponential, although the degree of nonexponentially depends strongly on the mutant and the temperature. We correlated the changes in decay time with mutation-induced changes in the redox potential of the ground state of the special pair. The qualitative form of the decays led us to explore a model based on a small Gaussian distribution of free energy gaps for the electron-transfer process. The model is used to estimate the reorganization energy arising from low-frequency protein and intramolecular modes coupled to the electron transfer. Our fitting procedure gives values of [le]250 and 500 cm[sup [minus]1] at 292 and 22 K, respectively. A consideration of possible errors leads us to conclude that the room temperature value could be no larger than twice the fitted value (i.e., [le]500 cm[sup [minus]1]). The implications of our results for the mechanism of primary charge separation are discussed. 89 refs., 9 figs., 2 tabs.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5067857
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 97:50; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CHLOROPHYLL
ELECTRON TRANSFER
CHEMICAL REACTION KINETICS
COMPILED DATA
ENERGY GAP
EXCITED STATES
FREE ENERGY
GAUSSIAN PROCESSES
MATHEMATICAL MODELS
MUTANTS
PHOTOSYNTHESIS
PHOTOSYNTHETIC BACTERIA
PHOTOSYNTHETIC REACTION CENTERS
PROTEINS
TEMPERATURE DEPENDENCE
BACTERIA
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DATA
ENERGY
ENERGY LEVELS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
KINETICS
MICROORGANISMS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYSICAL PROPERTIES
PHYTOCHROMES
PIGMENTS
PORPHYRINS
REACTION KINETICS
SYNTHESIS
THERMODYNAMIC PROPERTIES
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400201 - Chemical & Physicochemical Properties