title: Characterization of a 7Fe ferredoxin isolated from the marine denitrifier Pseudomonas nautica strain 617: spectroscopic and electrochemical studies.
abstract: A 7Fe ferredoxin, isolated from the marine denitrifier Pseudomonas nautica strain 617, was characterized. The NH2-terminal sequence analysis, performed until residue number 56, shows a high similarity with the 7Fe ferredoxins isolated from Azotobacter vinelandii, Pseudomonas putida, and Pseudomonas stutzeri. EPR and NMR spectroscopies identify the presence of both [3Fe-4S] and [4Fe-4S] clusters, with cysteinyl coordination. The electrochemical studies on [Fe-S] clusters show that a fast diffusion-dominated electron transfer, promoted by Mg(II), takes place between the ferredoxin and the glassy carbon electrode. Square wave voltammetry studies gave access to the electrosynthesis of a 4Fe center formed within the [3Fe-4S] core. The [3Fe-4S] cluster exhibited two reduction potentials at -175 and -680 +/- 10 mV and the [4Fe-4S] cluster was characterized by an unusually low reduction potential of -715 +/- 10 mV, at pH 7.6
authors.affiliation: Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Portugal.
authors.forename: A L
authors.initials: AL
authors.lastname: Macedo
authors.forename: S
authors.initials: S
authors.lastname: Besson
authors.forename: C
authors.initials: C
authors.lastname: Moreno
authors.forename: G
authors.initials: G
authors.lastname: Fauque
authors.forename: J J
authors.initials: JJ
authors.lastname: Moura
authors.forename: I
authors.initials: I
authors.lastname: Moura
mesh_terms: D000595:Amino Acid Sequence; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D005288:Ferredoxins / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011549:Pseudomonas / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D005288:Ferredoxins