FIGURE 4.

Auxiliary cluster positions in SPASM/Twitch enzymes. Distances are shown as follows: SAM cluster to Aux cluster (green dashed lines); hydrogen atom abstraction position on substrate to Aux cluster (black dashed lines); and hydrogen atom abstraction position to C5′ of SAM (purple dashed lines). A, BtrN. DOIA, 2-deoxy-scyllo-inosamine. B, anSME with peptide bound (green). C, MoaA. D, hypothetical AlbA model estimating distances between the site of hydrogen atom abstraction on a peptide glycine to the site of thioether bond formation on the sulfur of a peptide cysteine (red dashed line) and to the Aux cluster (blue dashed line). E, BioB with DTB bound. F, RimO.