Proton Magnetic Resonance Studies of the Ferredoxins from Spinach and Parsley

Poe, Martin; Phillips, William D.; Glickson, Jerry D.; McDonald, C. C.; Pietro, Anthony San

doi:10.1073/pnas.68.1.68

Cited by 56 publications

(29 citation statements)

References 15 publications

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“…All spectra were recorded at 20 °C, 220 MHz, and 20 kHz modulation frequency by continuous wave repetitive scanning on the Varian instrument in the Chemistry Division at Argonne National Laboratories. The results are quite similar to those obtained with spinach ferredoxin by Salmeen and Palmer [3] and Poe et al [2]. With oxidized ferredoxin (top trace) a broad resonance representing 6 to 9 protons was observed at 34 ppm (downfield from trisilyltetradeuterio sodium propionate) while Salmeen and Palmer [3] Fig.…”

Section: Reduced Ferredoxinsupporting

confidence: 88%

See 1 more Smart Citation

On the nature of the iron sulfur cluster in a deuterated algal ferredoxin

Anderson

Dunham

Sands

et al. 1975

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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A protonated and a completely deuterated two-iron algal ferredoxin from Synechococcus lividus have been studied by optical, electron paramagnetic resonance, electron-nuclear double resonance, proton magnetic resonance and Mossbauer spectroscopies; temperature dependent magnetic susceptibility measurements are reported as well. These studies have confirmed the electron localized model of the active center in the two-iron ferredoxins, as previously deduced from studies of spinach ferredoxin, have yielded much more precise spectroscopic parameters for this center, and have thus greatly increased the confidence in this model.

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Section: Reduced Ferredoxinsupporting

confidence: 88%

“…The results of EPR, ENDOR, Mossbauer, PMR and magnetic susceptibility are presented here, but when the results are identical to those of spinach ferredoxin the reader is referred to the previous references [1][2][3][4][5][6][7][8] for a more complete discussion.…”

Section: Introductionmentioning

confidence: 99%

On the nature of the iron sulfur cluster in a deuterated algal ferredoxin

Anderson

Dunham

Sands

et al. 1975

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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“…Proton magnetic resonance (PMR) spectra show that the rate of electron transfer between the two iron atoms at 300°K is much slower than IO4 sec -1 (ref. 5).…”

Section: Structure Of the Active Sitementioning

confidence: 99%

On the structure of the iron-sulfur complex in the two-iron ferredoxins

Dunham

Palmer

Sands

et al. 1971

Biochimica et Biophysica Acta (BBA) - Bioenergetics

142

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Recent spectroscopic and magnetic susceptibility studies of the iron center in the two-iron ferredoxins provide criteria which any model for the iron-sulfur complex in these proteins must satisfy. These criteria are most stringent for parsley and spinach ferredoxin: the reduced proteins contain a high-spin ferric atom antiferromagnetically exchange-coupled (presumably via sulfide bridging ligands) to a high-spin ferrous atom. In the oxidized proteins the iron atoms are antiferromagnetically spin-coupled, high-spin ferric atoms. Arguments are given to substantiate the claim that the ferrousatom in the reduced protein is ]]gated by four sulfur atoms in a distorted tetrahedral configuration : two are the bridging sulfides, two are cysteinyl sulfurs. A treatment of proton contact shifts based upon the above model is pertinent to proton magnetic resonance data already available and provides a means to identify directly the ligands at both iron atoms via further PMR experiments. * This is one of a series of papers describing the electronic properties of several of the two-irontwo (labile) sulfur proteins; related publications contain the results of experiments on ENDOR 1 (called I), the M6ssbauer 2 (calledlI), magnetic susceptibility a (called III) and infrared, optical and circular dichroism spectra 3 (called IV).

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“…The most important one is the fact that the oxidized protein has a silent EPR signal at low temperatures, indicative of antiferromagnetic coupling between the two iron atoms, each one with its own spin, S = 5/2. However, as the temperature is raised, an EPR signal appears, and the cluster becomes paramagnetic (Poe et al, 1971). The main effect derived from the presence of a paramagnetic center is to shift and broaden the NMR signals.…”

Section: Introductionmentioning

confidence: 99%

A molecular dynamics study of Fe2S2 putidaredoxin: multiple conformations of the C-terminal region

Roitberg

1997

Biophysical Journal

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Putidaredoxin (Pdx) plays an essential role as an electron donor and effector in the biochemical cycle involving cytochrome P450cam. Only recently has an NMR-derived structure for this protein been published, but because of the presence of a paramagnetic Fe2S2 center, the NMR assignment could not be completed for residues within a region of 8 A around the active site. That region was modeled by homology with a related protein. The structural refinement for those experiments was done in vacuum, without the use of electrostatic terms in the force field. The present manuscript will describe and discuss a series of long-time, unrestrained, solution molecular dynamic runs for this system. Results will be presented that construct a molecular-level picture that rationalizes experimental results concerning the conformation and mobility of the C-terminal residue Trp106. At least two different conformers are found for this residue during the simulations. The time scale for interconversion between them is found to be in the subnanosecond regime. The results presented here open the possibility for studying binding and electron transfer between Pdx and P450cam, in a framework that allows for dynamical information to be used during the computational process, instead of the single structures deposited on the protein data base.

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Proton Magnetic Resonance Studies of the Ferredoxins from Spinach and Parsley

Cited by 56 publications

References 15 publications

On the nature of the iron sulfur cluster in a deuterated algal ferredoxin

On the nature of the iron sulfur cluster in a deuterated algal ferredoxin

On the structure of the iron-sulfur complex in the two-iron ferredoxins

A molecular dynamics study of Fe2S2 putidaredoxin: multiple conformations of the C-terminal region

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