Synthetic analogues of the active sites of iron-sulfur proteins.  XIII.  Further electronic structural relationships between the analogues [Fe2S2(SR)4]2- and the active sites of oxidized 2Fe-2S* proteins

Gillum, W. O.; Frankel, Richard B.; Foner, S.; Holm, R. H.

doi:10.1021/ic50159a023

Cited by 66 publications

(59 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The slopes of α = −0.620 e −1 a 0 3 mm s −1 or −0.744 e −1 a 0 3 mm s −1 from method 1 and method 2 above, respectively, are steeper than the published values ranging between −0.3 and −0.5 e −1 a 0 3 mm s −1 . 16, 18, 83 We note that the two models with the largest deviation from the correlation line in Figure S1A are [Fe(S 2 - o -Xyl) 2 ] − and [Fe 2 S 2 (S 2 - o -Xyl) 2 ] 2− , and their experimental isomer shifts of 0.13 mm s −1 and 0.17 mm s −1 , respectively, 84, 85 are much lower than values typically used for [Fe III -S] complexes in training sets (for example Refs. 16, 17, 83).…”

Section: Resultsmentioning

confidence: 82%

Comparative Assessment of the Composition and Charge State of Nitrogenase FeMo-Cofactor

Harris

Szilágyi

2011

Inorg. Chem.

View full text Add to dashboard Cite

A significant limitation in our understanding of the molecular mechanism of biological nitrogen fixation is the uncertain composition of the FeMo-cofactor (FeMo-co) of nitrogenase. In this study we present a systematic, density functional theory-based evaluation of spin coupling schemes, iron oxidation states, ligand protonation states, and interstitial ligand composition using a wide range of experimental criteria. The employed functionals and basis sets were validated with molecular orbital information from X-ray absorption spectroscopic data of relevant iron-sulfur clusters. Independently from the employed level of theory, the electronic structure with the greatest number of antiferromagnetic interactions corresponds to the lowest energy state for a given charge and oxidation state distribution of the iron ions. The relative spin state energies of resting and oxidized FeMo-co already allowed the exclusion of certain iron oxidation state distributions and interstitial ligand compositions. Geometry optimized FeMo-co structures of several models further eliminated additional states and compositions, while reduction potentials indicated a strong preference for the most likely charge state of FeMo-co. Mössbauer and ENDOR parameter calculations were found to be remarkably dependent on the employed training set, density functional and basis set. Overall, we found that a more oxidized [MoIV-2FeII-5FeIII-9S2−-C4−] composition with a hydroxyl-protonated homocitrate ligand satisfies all of the available experimental criteria, and is thus favored over the currently preferred composition of [MoIV-4FeII-3FeIII-9S2−-N3−] from the literature.

show abstract

Section: Resultsmentioning

confidence: 82%

Comparative Assessment of the Composition and Charge State of Nitrogenase FeMo-Cofactor

Harris

Szilágyi

2011

Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…2 Magnetic data have been determined for only few synthetic [2Fe2S] clusters in their diferric form [2], and the magnitude of the antiferromagnetic coupling in 1-3 is at the upper end of what has previously been reported (e.g. J $ À150 cm À1 for (NEt 4 ) 2 [(S 2 -o-Xyl)Fe(l-S) 2 Fe(S 2 -o-Xyl) [29]). …”

Section: Resultsmentioning

confidence: 99%

Relatively stable N-ligated [2Fe2S]2+ clusters with dipyrromethane capping ligands

Ballmann¹,

Sun²,

Dechert³

et al. 2007

Journal of Inorganic Biochemistry

View full text Add to dashboard Cite

“…[4,5] Trotz vielfältiger Bemühungen konnte hingegen noch kein asymmetrisch koordinierter Cluster, der die besondere Ligandsituation der Eisen-Schwefel-Proteine des Rieske-Typs nachbildet, synthetisiert werden. [6] Hier berichten wir nun von der Synthese sowie der spektroskopischen und kristallographischen Charakterisierung der ersten synthetischen Die neuartige Clusterverbindung des Rieske-Typs 4 kann ausgehend von 2 hergestellt werden, ist jedoch besser in einer Eintopf-Synthese bei À40 8C erhältlich, indem nacheinander zunächst das Lithiumsalz des {N 2 }-Liganden und daraufhin der deprotonierte {S 2 }-Ligand, o-Xylol-a,a'-dithiol, [9] zu einer Lösung von 1 gegeben werden (Schema 1). [9] Eisenzentren in 3 und 5 auf (Tabelle 1 und Tabelle S6 in …”

unclassified

Ein synthetisches Analogon für [2Fe‐2S]‐Cluster des Rieske‐Typs

et al. 2008

View full text Add to dashboard Cite

Wie das biologische Vorbild weist das synthetische Modell für die [2Fe‐2S]‐Cluster des Rieske‐Typs einen charakteristisch niedrigen gav‐Wert im EPR‐Spektrum der reduzierten [2Fe‐2S]+‐Form auf. Erstmals konnten strukturelle und spektroskopische Merkmale der proteingebundenen Cluster naturgetreu nachbildet werden. Das Bild zeigt die Molekülstruktur des Modells (grau C, rot Fe, blau N, gelb S) sowie sein EPR‐Spektrum nach Reduktion (unten) und sein Mößbauer‐Spektrum (oben).

show abstract

Synthetic analogues of the active sites of iron-sulfur proteins. XIII. Further electronic structural relationships between the analogues [Fe2S2(SR)4]2- and the active sites of oxidized 2Fe-2S* proteins

Cited by 66 publications

References 33 publications

Comparative Assessment of the Composition and Charge State of Nitrogenase FeMo-Cofactor

Comparative Assessment of the Composition and Charge State of Nitrogenase FeMo-Cofactor

Relatively stable N-ligated [2Fe2S]2+ clusters with dipyrromethane capping ligands

Ein synthetisches Analogon für [2Fe‐2S]‐Cluster des Rieske‐Typs

Contact Info

Product

Resources

About