Figure 4.

A comparison of the active sites in wt and C118A RlmN. X-ray structures of C118A RlmN were determined in the presence (A) and absence (B) of SAM and compared to the analogous wt RlmN structures with (C) and without (D) SAM (PDB accession codes 3RFA and 3RF9, respectively). Selected residues and SAM are shown in stick format and the [4Fe–4S]²⁺ cluster is shown as a space-filling model. Arrows in panels B and D illustrate conformational changes associated with absence of the SAM cosubstrate.