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G. Feher
University of California, San Diego
83Publications
40H-index
6,338Citations
Publications 83
Newest
#1Marco FloresH-Index: 15
#2R.A. IsaacsonH-Index: 22
Last.G. FeherH-Index: 40
view all 6 authors...
The geometry of the hydrogen bonds to the two carbonyl oxygens of the semiquinone Q �� in the reaction center (RC) from the photosynthetic purple bacterium Rhodobacter sphaeroides R-26 were determined by fitting a spin Hamiltonian to the data derived from 1 H and 2 H ENDOR spectroscopies at 35 GHz and 80 K. The experiments were performed on RCs in which the native Fe 21 (high spin) was replaced by diamagnetic Zn 21 to prevent spectral line broadening of the Q �� due to magnetic coupling with the...
#1Marco Flores (UCSD: University of California, San Diego)H-Index: 15
#2R.A. Isaacson (UCSD: University of California, San Diego)H-Index: 22
Last.G. Feher (UCSD: University of California, San Diego)H-Index: 40
view all 6 authors...
Abstract The geometry of the hydrogen bonds to the two carbonyl oxygens of the semiquinone QA ⋅ ⁡ − in the reaction center (RC) from the photosynthetic purple bacterium Rhodobacter sphaeroides R-26 were determined by fitting a spin Hamiltonian to the data derived from 1 H and 2 H ENDOR spectroscopies at 35GHz and 80K. The experiments were performed on RCs in which the native Fe 2+ (high spin) was replaced by diamagnetic Zn 2+ to prevent spectral line broadening of the QA ⋅ ⁡ − due to magnetic co...
56 CitationsSource
#1Marco Flores (UCSD: University of California, San Diego)H-Index: 15
#2R.A. Isaacson (UCSD: University of California, San Diego)H-Index: 22
Last.G. Feher (UCSD: University of California, San Diego)H-Index: 40
view all 6 authors...
Hydrogen bonds are important in determining the structure and function of biomolecules. Of particular interest are hydrogen bonds to quinones, which play an important role in the bioenergetics of respiration and photosynthesis. In this work we investigated the hydrogen bonds to the two carbonyl oxygens of the semiquinone in the well-characterized reaction center from the photosynthetic bacterium Rhodobacter sphaeroides R-26. We used electron paramagnetic resonance and electron nuclear double res...
26 CitationsSource
#1Mark L. PaddockH-Index: 32
#2C. ChangH-Index: 6
Last.Okamura MyH-Index: 22
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The photosynthetic reaction center (RC) from purple bacteria converts light into chemical energy. Although the RC shows two nearly structurally symmetric branches, A and B, light-induced electron transfer in the native RC occurs almost exclusively along the A-branch to a primary quinone electron acceptor QA. Subsequent electron and proton transfer to a mobile quinone molecule QB converts it to a quinol, QBH2. We report the construction and characterization of a series of mutants in Rhodobacter s...
27 CitationsSource
#1Mark L. Paddock (UCSD: University of California, San Diego)H-Index: 32
#2G. Feher (UCSD: University of California, San Diego)H-Index: 40
Last.Melvin Y. Okamura (UCSD: University of California, San Diego)H-Index: 34
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Abstract The focus of this minireview is to discuss the state of knowledge of the pathways and rates of proton transfer in the bacterial reaction center (RC) from Rhodobacter sphaeroides. Protons involved in the light driven catalytic reduction of a quinone molecule QB to quinol QBH2 travel from the aqueous solution through well defined proton transfer pathways to the oxygen atoms of the quinone. Three main topics are discussed: (1) the pathways for proton transfer involving the residues: His-H1...
87 CitationsSource
#1Marco Flores (UCSD: University of California, San Diego)H-Index: 15
#2R.A. Isaacson (UCSD: University of California, San Diego)H-Index: 22
Last.Wolfgang Lubitz (MPG: Max Planck Society)H-Index: 64
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Abstract ENDOR spectroscopy at 35 GHz and 80 K was used to study the radical anion of 1,4-benzoquinone (BQ) in water and various alcohols. BQ -d 4 in H 2 O and BQ -h 4 in D 2 O were investigated with the aim to obtain information on the hydrogen bonds between the quinone oxygen and the respective solvent. The observed spectra were analyzed using the GENDOR program for the simulation of orientationally selected powder ENDOR spectra. From the spectral simulations the hyperfine coupling and nuclear...
46 CitationsSource
#1Mark L. PaddockH-Index: 32
#2Laura B. SagleH-Index: 18
Last.Okamura MyH-Index: 22
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The bacterial photosynthetic reaction center (RC) uses light energy to catalyze the reduction of a bound quinone molecule QB to quinol QBH2. In RCs from Rhodobacter sphaeroides the protons involved in this process come from the cytoplasm and travel through pathways that involve His-H126 and His-H128 located near the proton entry point. In this study, we measured the pH dependence from 4.5 to 8.5 of the binding of the proton transfer inhibitor Cd 2+ , which ligates to these surface His in the RC ...
27 CitationsSource
#1Mark L. PaddockH-Index: 32
#2Pia ÄdelrothH-Index: 28
Last.J. T. BeattyH-Index: 13
view all 5 authors...
The bacterial reaction center (RC) converts light into chemical energy through the reduction of an internal quinone molecule QB to QBH2. In the native RC, proton transfer is coupled to electron transfer and is not rate-controlling. Consequently, proton transfer is not directly observable, and its rate was unknown. In this work, we present a method for making proton transfer rate-controlling, which enabled us to determine its rate. The imidazole groups of the His-H126 and His-H128 proton donors, ...
22 CitationsSource
#1Tetreault MH-Index: 1
#2S. H. RongeyH-Index: 6
Last.Okamura MyH-Index: 22
view all 4 authors...
34 CitationsSource
#1Mark L. PaddockH-Index: 32
#2Pia ÄdelrothH-Index: 28
Last.Okamura MyH-Index: 22
view all 6 authors...
28 CitationsSource
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