pfam10418: DHODB_Fe-S_bind (This model is not part of the current CDD release)
Iron-sulfur cluster binding domain of dihydroorotate dehydrogenase B
Lactococcus lactis is one of the few organisms with two dihydroorotate dehydrogenases, DHODs, A and B. The B enzyme is a prototype for DHODs in Gram-positive bacteria that use NAD+ as the second substrate. DHODB is a hetero-tetramer composed of a central homodimer of PyrDB subunits resembling the DHODA structure and two PyrK subunits along with three different cofactors: FMN, FAD, and a [2Fe-2S] cluster. The [2Fe-2S] iron-sulfur cluster binds to this C-terminal domain of the PyrK subunit, which is at the interface between the flavin and NAD binding domains and contains three beta-strands. The four cysteine residues at the N-terminal part of this domain are the ones that bind, in pairs, to the iron-sulfur cluster. The conformation of the whole molecule means that the iron-sulfur cluster is localised in a well-ordered part of this domain close to the FAD binding site. The FAD and and NAD binding domains are FAD_binding_6, pfam00970 and NAD_binding_1, pfam00175.