2.1.1.224	Fe-S-clusters	contains a 4Fe-4S cluster. Radical-SAM enzymes contain a [4Fe-4S]+ cluster that is coordinated by the three conserved cysteine thiolate side chains in the CX3CX2C motif and one molecule of S-adenosyl-L-methionine	705983	
2.1.1.224	Fe2+	4Fe-4S cluster. Fe-S clusters are of structural, as well as functional, importance to Cfr. Radical-SAM enzymes use an Fe-S cluster to generate the 5'-deoxyadenosyl radical from SAM, enabling them to modify intrinsically unreactive centres such as adenosine C8. Anaerobic purification from Azotobacter vinelandii Cfr	720968	
2.1.1.224	Fe2+	Clostridioides difficile Cfr contains an additional Cys-rich C-terminal domain that binds a mononuclear Fe2+ ion in a rubredoxin-type Cys4 motif. The rate of turnover is decreased upon disruption of the Fe2+-binding site by Zn2+ substitution or ligand mutation	758141	
2.1.1.224	Iron	the enzyme requires an intact [4Fe-S] cluster for catalysis	704203	
2.1.1.224	Mg2+	required	718587, 755810, 758141