Fig. 1: Molecular editing of MMOR and MMOH for miniaturizing sMMO.
a, b Primary (a) and tertiary structure (b) of MMOR. c, d Primary structure of MMOHα (c) and tertiary structure of MMOH (d). The gray-colored regions in (a–d) were removed from the native structure for constructing the sMMO miniatures (mini-sMMOs). The gray region in (a, b) indicates the ferredoxin domain, while the remaining cyan region represents the FAD domain. The rainbow-colored regions in (c, d) indicate the eight helices of MMOHα (αA to αH in rainbow order) surrounding the diiron center (depicted as pink spheres in (d)). In (d), the MMOHα subunit in the MMOH protomer is represented by ribbons, while the MMOHβ and MMOHγ subunits and the other protomers in the dimer are represented as wires. The FAD domain of MMOR (defined as RFAD) in (a, b) and the eight helices and white-colored regions in MMOHα (defined as ΔHα) in (c, d) are included in the mini-sMMOs. e Structure of ΔHα with center-of-mass positions (colored spheres) of RFAD poses, obtained from PPD simulations, indicating the bimodal distribution of RFAD poses in the canyon and NTH (N-terminal half). The docking score of the poses is indicated by a color gradient that ranges from blue (representing a low score) to red (representing a high score). The N-terminus of ∆Hα is indicated by an arrow.
