Abstract: Objective　To prepare purified human peroxisome proliferator-activated receptor-ligand binding domain (PPARγ-LBD) peptide segment and study the binding strength of N-3-oxododecanoyl-l-homoserine lactone (3-O-C12-HSL) to PPARγ-LBD. Methods　The binding site of 3-O-C12-HSL to PPARγ was predicted by molecular docking. PPARγ-LBD gene was synthesized and inserted into pET28b plasmid. The recombinant peptide fragment was induced by IPTG after identification and analyzed by SDS-PAGE and Western blot assay. The binding kinetic parameters of 3-O-C12-HSL and PPARγ-LBD were measured by surface plasmon resonance technique. Results　Results of molecular docking showed that 3-O-C12-HSL formed hydrogen bond with Tyr473 and Tyr327 of PPARγ-LBD, and the terminal flexible carbon chain of 3-O-C12-HSL formed hydrophobic interaction with the residues of Met329 and Leu330 of PPARγ-LBD. The human PPARγ-LBD peptide fragment was prepared, and the molecular weight of PPARγ-LBD was 25~35 ku consistent with that of Western blot assay and SDS-PAGE. The binding affinity constant of 3-O-C12-HSL with PPARγ was 1.65×10-4 mol/L, the binding rate constant was 1.06×102/ms, and the dissociation rate constant was 1.75×10-2/s. Conclusion　The binding ability of 3-O-C12-HSL to PPARγ-LBD functional region is stronger than that of PPARγ-specific antagonist GW9662, which provides experimental basis for preparing specific targeted drugs against 3-O-C12-HSL.

Key words: Pseudomonas aeruginosa, PPAR gamma, molecular docking simulation, surface plasmon resonance technique, N-3-oxododecanoyl-L-homoserine lactone, ligand binding domain