Schizosaccharomyces pombe (Sp) ferredoxin contains a C-terminal electron transfer protein ferredoxin domain (etp(Fd)) that is homologous to adrenodoxin. The ferredoxin has been characterized by spectroelectrochemical methods, and Mössbauer, UV-Vis and circular dichroism spectroscopies. The Mössbauer spectrum is consistent with a standard diferric [2Fe-2S](2+) cluster. While showing sequence homology to vertebrate ferredoxins, the E°' and the reduction thermodynamics for etp(Fd) (-0.392 V) are similar to plant-type ferredoxins. Relatively stable Cys to Ser derivatives were made for each of the four bound Cys residues and variations in the visible spectrum in the 380-450 nm range were observed that are characteristic of oxygen ligated clusters, including members of the [2Fe-2S] cluster IscU/ISU scaffold proteins. Circular dichroism spectra were similar and consistent with no significant structural change accompanying these mutations. All derivatives were active in an NADPH-Fd reductase cytochrome c assay. The binding affinity of Fd to the reductase was similar, however, V(max) reflecting rate limiting electron transfer was found to decrease ~13-fold. The data are consistent with relatively minor perturbations of both the electronic properties of the cluster following substitution of the Fe-bond S atom with O, and the electronic coupling of the cluster to the protein.
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|Titolo:||Redox chemistry of the Schizosaccharomyces pombe ferredoxin electron-transfer domain and influence of Cys to Ser substitutions.|
|Autori:||S. p., Wu; M., Bellei; Mansy, Sheref Samir; G., Battistuzzi; M., Sola; J. A., Cowan|
|Titolo del periodico:||JOURNAL OF INORGANIC BIOCHEMISTRY|
|Anno di pubblicazione:||2011|
|Codice identificativo Scopus:||2-s2.0-79955105428|
|Codice identificativo Pubmed:||21497579|
|Codice identificativo ISI:||WOS:000291131600007|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.jinorgbio.2011.03.004|
|Appare nelle tipologie:||03.1 Articolo su rivista (Journal article)|