Disease relevance of fixX

• Second gene (nifH*) coding for a nitrogenase iron protein in Azotobacter chroococcum is adjacent to a gene coding for a ferredoxin-like protein [1].
• Synthesis of the ferredoxin-like protein FdxN from Rhizobium meliloti bacteroids as a fusion protein in Escherichia coli [2].

High impact information on fixX

• The enzyme contains four ferredoxin-like Cys groups in the electron transfer subunit, DmsB, and an additional group of Cys residues in the catalytic subunit, DmsA [3].
• The results show the reduction potentials in the midrange for ferredoxin-like [4Fe-4S] clusters [4].
• This protein is designated as PFLP (plant ferredoxin-like protein) by virtue of its high homology with plant ferredoxin protein containing an N-terminal signal peptide responsible for chloroplast targeting and a putative 2Fe-2S domain responsible for redox activity [5].
• The reductase partner comprises flavin mononucleotide- and NADH-binding motifs and a [2Fe2S] ferredoxin-like center [6].
• The deduced human ETF-QO sequence predicts a protein containing 617 amino acids (67 kDa), two domains associated with the binding of the AMP moiety of the FAD prosthetic group, two membrane helices and a motif containing four cysteine residues that is frequently associated with the liganding of ferredoxin-like iron-sulfur clusters [7].

Biological context of fixX

• In contrast, ferredoxin-like proteins, which are encoded by nifB-associated genes, are not required for nitrogen fixation in all other organisms analysed so far [8].

Associations of fixX with chemical compounds

• The 12 cysteine residues present in FrdB form 3 ferredoxin-like clusters, whereas the 12 cysteines of FrdA are not clustered [9].
• We report here a simple system for the functional expression of various P450 genes using the reductase domain of this P450RhF, which comprises flavin mononucleotide- and nicotinamide adenine dinucleotide phosphate binding motifs and a [2Fe2S] ferredoxin-like center [10].

References