Enzyme structures were obtained from the PDB (IDs: 5UCW, 8DSG) and truncated to a single chain (A) for SMART analysis. Due to the structural significance of the bridging water (w0) in P411-PFA (8DSG), this molecule was retained in the truncated structure. Remaining water, ion, and non-covalently bound residues were removed from each enzyme to allow for assessment of the empty cavity. The linear probe, LinH_6, was docked at the axial position of the Fe site to represent a bound carbene intermediate.