FIGURE 3. Structural comparisons.
From the following article:
Crystal structure of the non-haem iron halogenase SyrB2 in syringomycin biosynthesis
Leah C. Blasiak, Frédéric H. Vaillancourt, Christopher T. Walsh and Catherine L. Drennan
Nature 440, 368-371 (16 March 2006)
doi:10.1038/nature04544
a, View of the active site from a structural alignment of SyrB2 (grey) and FIH-1 (cyan). Alignment was done with LSQMAN29. Ninety-nine residues (33% of SyrB2) align with a root mean square deviation of 1.95 Å. Iron and chloride from SyrB2 are shown in grey and green, respectively; iron from FIH-1 is shown in cyan. Labelled amino acids correspond to SyrB2. b, Cut-away view of SyrB2 with bound 
KG and no iron. Two channels lead to the active site. Phe 196 is not visible owing to clipping planes. c, Cut-away view of Cl–Fe(ii)–KG–SyrB2 in a similar orientation to b, but the molecular surface is clipped to show Phe 196 (red) clearly. SyrB2 closes down around the bound iron (brown) and chloride (green), leaving only one opening to the active site. The water molecule located at the predicted dioxygen-binding site is shown in cyan. Scale bar, 
15 Å. d, KG–SyrB2 (magenta) and Cl–Fe(ii)–KG–SyrB2 (blue). Arrows show change in conformation on binding of iron and chloride.
