- A: few secondary structure elements
- X: Dihydroorotate dehydrogenase B PyrK subunit 2Fe-2S cluster-binding domain
- H: Dihydroorotate dehydrogenase B PyrK subunit 2Fe-2S cluster-binding domain
- T: Dihydroorotate dehydrogenase B PyrK subunit 2Fe-2S cluster-binding domain
- F: DHODB_Fe-S_bind