Figure 5
From: Mapping the key residues of SufB and SufD essential for biosynthesis of iron-sulfur clusters
Model for the role of the SufBCD complex during Fe-S cluster biosynthesis. Sulfur (S0) is extracted from the substrate L-cysteine by the action of SufS and delivered via SufE to SufBC254 of the SufBCD complex in the form of persulfide (-SSH). The bound S0 is reduced to S2−, presumably by FADH2, released from SufBC254, and migrates through the hydrophilic tunnel that traverses the β-helix core domain of SufB from SufBC254 to SufBC405. Dimerization of SufC occurs upon binding to ATP, which induces a large conformational change at the SufB-SufD interface, where the Fe-S cluster is assembled using SufBC405, SufBE434 and SufDH360 as essential ligands in combination with a fourth redundant ligand that is provided by one of the three residues, SufBE432, SufBH433, or SufDC358.
