ABSTRACT
The lack of new drugs that are effective against antibiotic-resistant bacteria has caused increasing concern in global public health. Based on this study, we report development of a modified antimicrobial drug through structure-based drug design (SBDD) and modular synthesis. The optimal modified compound, F8, was identified, which demonstrated in vitro and in vivo broad-spectrum antibacterial activity against drug-resistant bacteria and effectively mitigated the development of resistance. F8 exhibits significant bactericidal activity against bacteria resistant to antibiotics such as methicillin, polymyxin B, florfenicol (FLO), doxycycline, ampicillin and sulfamethoxazole. In a mouse model of drug-resistant bacteremia, F8 was found to increase survival and significantly reduce bacterial load in infected mice. Multi-omics analysis (transcriptomics, proteomics, and metabolomics) have indicated that ornithine carbamoyl transferase (arcB) is a antimicrobial target of F8. Further molecular docking, Isothermal Titration Calorimetry (ITC), and Differential Scanning Fluorimetry (DSF) studies verified arcB as a effective target for F8. Finally, mechanistic studies suggest that F8 competitively binds to arcB, disrupting the bacterial cell membrane and inducing a certain degree of oxidative damage. Here, we report F8 as a promising candidate drug for the development of antibiotic formulations to combat antibiotic-resistant bacteria-associated infections.
Subject(s)
Anti-Bacterial Agents , Drug Design , Microbial Sensitivity Tests , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Animals , Mice , Molecular Docking Simulation , Drug Resistance, Bacterial/drug effects , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Bacteremia/drug therapy , Bacteremia/microbiology , Drug Resistance, Multiple, Bacterial/drug effects , FemaleABSTRACT
A full-length cDNA of 794 bp encoding a putative copper/zinc-superoxide dismutase (Cu/Zn-SOD) from Pagrus major was cloned by the PCR approach. Nucleotide sequence analysis of this cDNA clone revealed that it comprises a complete open reading frame coding for 154 amino acid residues. The deduced amino acid sequence showed high similarity (53-91%) with the sequences of Cu/Zn-SOD from other species. Computer analysis of the residues required for coordinating copper (His-47, 49, 64, and 121) and zinc (His-64, 72, 81, and Asp-84), as well as the two cysteines (58 and 147) that form a single disulfide bond, were well conserved among all reported Cu/Zn-SOD sequences. To further characterize the Pagrus major Cu/Zn-SOD, the coding region was subcloned into an expression vector, pET-20b(+), and transformed into Escherichia coli BL21(DE3). The expression of the Cu/Zn-SOD was confirmed by enzyme activity stained on a native-gel and purified by Ni(2+)-nitrilotriacetic acid Sepharose superflow. Dimer was the major form of the enzyme in equilibrium. The dimerization of the enzyme was inhibited under acidic pH (below 4.0 or higher than 10.0). The half-life was 8.6 min and the inactivation rate constant (k(d)) was 9.69 x 10(-2) min(-1) at 70 degrees C. The enzyme activity was not significantly affected under 4% SDS or 0.5 M imidazole. The enzyme was resistant to proteolysis by both trypsin and chymotrypsin.
