Rubredoxin, Small Modular nonheme iron binding domain containing a [Fe(SCys)4] center, present in rubrerythrin and nigerythrin and detected either N- or C-terminal to such proteins as flavin reductase, NAD(P)H-nitrite reductase, and ferredoxin-thioredoxin reductase. In rubredoxin, the iron atom is coordinated by four cysteine residues (Fe(S-Cys)4), and believed to be involved in electron transfer. Rubrerythrins and nigerythrins are small homodimeric proteins, generally consisting of 2 domains: a rubredoxin domain C-terminal to a non-sulfur, oxo-bridged diiron site in the N-terminal rubrerythrin domain. Rubrerythrins and nigerythrins have putative peroxide activity.
Jiyao W et al.(2023). "The conserved domain database in 2023.",