This superfamily entry represents the open reading frame SCO4226 of Streptomyces coelicolor A3(2), which encodes an 82-residue hypothetical protein. According to Pfam, most of these proteins are found in bacteria and archaea, though are functionally uncharacterised. Biochemical assays revealed that each SCO4226 dimer binds four nickel ions. Each subunit of SCO4226 dimer adopts a canonical ferredoxin-like fold with five beta-strands flanked by two alpha-helices. In the structure of Ni-SCO4226, four nickel ions are coordinated at the surface of the dimer. Further biochemical assays suggested that the binding of Ni2+ triggers the self-aggregation of SCO4226 in vitro. All these results suggested that SCO4226 acts as a nickel binding protein, probably required for nickel sequestration and/or detoxification. Additionally, there is a single completely conserved residue C that may be functionally important.

DOI:10.1371/journal.pone.0109660, PFAM:PF14026, DUF4242, INTERPRO:IPR025336