Fig. 4. Interaction between LovB and LovC is essential for the synthesis of DML.

a Nineteen models built by RosettaCM were chosen for protein docking simulation with LovC. Residues 695–757 (part of the MAT domain) are shown. Purple color denotes the successful docked model. b Energy funnel for MAT/LovB–LovC docking analysis. The plot of score vs. rmsd shows the ten lowest-energy decoys (dark green) with rmsd <2.2 Å. c LovB–LovC interface. Top, view of the isolated electron density of MAT/LovB and interacting LovC with fitted molecular models. Bottom, close-up view of the interface between MAT/LovB and LovC (amino acids within 4 Å). d Size exclusion chromatography profiles for the interaction between LovC and the MAT domain of LovB. The LovC mutant profile is indicated by a dashed line. Elution of the component protein(s) is marked in color. One representative gel panel from at least three independent experiments shows the purified MAT domain of LovB, LovC, and the LovC mutant detected by SDS-PAGE. Source data is provided as a Source Data file. e HPLC traces showing the products of the in vitro reactions catalyzed by LovB with LovC or LovC mutant. LovG was included in the reaction mixture to release the final products. The DML acid has calculated and experimentally determined m/z [M−H]⁻ values of 323.23 and 323.22, respectively. Top, the extracted-ion chromatogram profile; bottom, the HPLC chromatogram profile at λ = 330 nm.