Fig. 4

a. The active site of CalO6. A SAM molecule (colored sticks with C in green, N in blue, O in red, and S in yellow) was modeled to be bound to CalO6 similarly to its binding to RdmB (PDB ID: 1XDS [28]) with confidence based on highly superimposable SAM binding motifs of CalO6 and RdmB. The disordered middle domain is shown by the dashed curve. The SAM interacting residues are shown in orange sticks; the proposed catalytic His252 and a putative substrate binding Phe163 are shown as red sticks. b. Structure of the active site of RdmB in complex with SAM (same colors as panel a) and 11-deoxy-3-β-rhodomycin (blue sticks). The folded middle domain capping the active site is shown in red