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Cyanide is added to oxidized 1Fe and 2Fe superoxide reductase (SOR) for the putative ferric-(hydro)peroxo intermediate in the reaction of the enzymes with superoxide by using vibrational and ENDOR spectroscopies to study the properties of the active site paramagnetic iron center. Low temperature ENDOR data shows that the bound cyanide adopts three distinct conformations in Fe(III)-CN SOR.

Resonance Raman results indicate that the electron transfer from rubredoxin to the mononuclear iron active site is mediated via superexchange pathways. Data show extensive coupling between the iron-sulfur stretching mode and the vibrational mode of cysteine.

The spectroscopic studies of pyrococcus furiosus superoxide reductase are detailed. The ability cyanide to bind exogenous ligands to both the ferrous and ferric sites of superoxide reductase is consistent with an inner-sphere catalytic mechanism involving superoxide binding at the ferrous site to yield a ferric-hydroperoxo intermediate.

Results reveal that the hydrogen bond network contributed by the first 15 amino acid residues of aporubredoxin or their interaction with other parts of the protein confer thermostability to the bacterial apo- and holoaporubredoxins.

Research has been conducted on the blue non-heme iron protein superoxide reductase (SOR). The investigation of the crystal structure of SOR in the oxidized and reduced forms is described.

The c-type cytochrome, cyt c(y), which is a photooxidized reactor center reduction pathway for Rhodobacter capsulatus, is the electron carrier that allows soluble cyt c2-independent photosynthetic growth. The cyt c(y) is observed in bc1 complex-lacking strains in a minimal, rather than rich, growth medium.

[super 57]Fe Nuclear resonance vibrational spectroscopy (NRVS) is applied for identifying protein-bound dinitrosyl iron complexes. NRVS spectra for four iron dinitrosyl model compounds are used as benchmarks for identifying species formed in the reaction of Pyrrococcus furiosus ferredoxin D14C with nitric oxide.

A combination of sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory is used to study the structure of superoxide reductase (SOR). The sites with high positive charge in these compounds are found to have higher affinity for binding another anion.

The solution structure of the PF0610, which is a novel winged helix-turn-helix (wHTH) protein with a rubredoxin-like Zn ribbon as its W1 segment, is determined by using nuclear magnetic resonance (NMR). The novel structure might help in understanding the transcription regulatory processes in Pyrococcus furiosus.

The properties of the iron ligands of CN-SOR and CN-P450cam are compared through a combination of [(super).1.H], [(super.13.C], and [(super).14.N] ENDOR spectroscopy. Results show that the difference between the in-plane heme and out-of-plane dihedral [His.sub.4] ligation of P450cam and SOR, respectively, causes real differences in the distribution of spin density over the on-axis atoms.

The Fe(S(sub cys))4 site in reduced and oxidized rubredoxin (Rd) from Pyrococcus furiosus (Pf) is studied using (super 57)Fe nuclear resonance vibrational spectroscopy (NRVS). A normal mode analysis using a Urey-Bradley force field is undertaken to quantitatively interpret the NRVS spectra and to set the stage for analysis of seemingly more complex problems such as hydrogenase and nitrogenase.

Nuclear resonant inelastic X-ray scatting (NRIXS) data on FeS4 and FeH(D)(sub 6) model systems is presented. Fe-H stretches have high frequencies and little Fe motion and both factors will reduce NIRXS intensity.

The ferrodoxin (Fd) of the Pyrococcus furiosus is distinct from other Fds derived from hyperthermophilic bacteria since it exhibits a number of rare properties. The Fd of these archaeon strains were found to possess a highly-stable molecular heterogeneity, an Asp cluster ligand and a flexible disulfide bond. Although other hyperthermophilic archaea a 13-member alpha helix bond, that of Pyrococcus furiosus feature a number of extensions which lead to the formation of tertiary contacts.