Domain structure of the putative CysI and CysJ of A. ferrooxidans. (A) PFAM domain structure of the putative CysI of A. ferrooxidans (Af). PF03460 = nitrite/sulfite reductase ferrodoxin-like half domains and PF01077 = Nitrite and sulfite reductase 4Fe-4S binding and siroheme binding. The amino acid sequence of a conserved region at the C-terminus of the 4Fe-4S binding and siroheme binding domain is aligned with similar regions of CysI from the following organisms: Schizosaccharomyces pombe (gi 2330803) Bacillus subtilis (gi 2635856) and Thiocapsa roseopersicina (gi 1706268). The number refers to the amino acid position of the proposed Af CysI. Conserved amino acids are shown in red. The sequence of prosite motif PS00365, [STV]-G-C-x(3)-C-x(6)-[DE]-[LIVMF]-[GAT]-LIVMF] is underlined. The two C's of this motif (shown in bold) are presumptive iron-sulfur ligands. (B) PFAM domain structure of the putative CysJ of A. ferrooxidans. PF00258 = flavodoxin domain, PF00667 = FAD binding domain and PF00175 = NAD-binding domain .