Figure 2.

Functional characterization of T103C and T333C mutations of CYP121. The two sites selected for ¹⁹F-NMR labeling are nearly equidistant from the heme iron center (A). Both mutants are capable of binding to Adx and supporting electron transfer, as indicated by EDC cross-linking (B) and reconstituted functional assays (p < 0.05) (C). Panels (D–F) summarize type-I absorbance difference spectra and saturation plots resulting from titrations with cYY. The T103C mutant results in a modest decrease in both total cYY converted to mycocyclosin as well as the maximum change in absorbance. All binding data were acquired in triplicate and fit using the one-site binding equation. Error bars are smaller than data point markers.