Identification of novel potent bicyclic peptide deformylase inhibitors.

Screening of our compound collection using Staphylococcus aureus Ni-Peptide deformylase (PDF) afforded a very potent PDF inhibitor with an IC(50) in the low nanomolar range but with poor antibacterial activity (MIC). Three-dimensional structural information obtained from Pseudomonas aeruginosa Ni-PDF complexed with the inhibitor suggested the synthesis of a variety of analogues that would maintain high binding affinity while attempting to improve antibacterial activity. Many of the compounds synthesized proved to be excellent PDF-Ni inhibitors and some showed increased antibacterial activity in selected strains.

Structure analysis of peptide deformylases from Streptococcus pneumoniae, Staphylococcus aureus, Thermotoga maritima and Pseudomonas aeruginosa: snapshots of the oxygen sensitivity of peptide deformylase.

Peptide deformylase (PDF) has received considerable attention during the last few years as a potential target for a new type of antibiotics. It is an essential enzyme in eubacteria for the removal of the formyl group from the N terminus of the nascent polypeptide chain. We have solved the X-ray structures of four members of this enzyme family, two from the Gram-positive pathogens Streptococcus pneumoniae and Staphylococcus aureus, and two from the Gram-negative bacteria Thermotoga maritima and Pseudomonas aeruginosa. Combined with the known structures from the Escherichia coli enzyme and the recently solved structure of the eukaryotic deformylase from Plasmodium falciparum, a complete picture of the peptide deformylase structure and function relationship is emerging. This understanding could help guide a more rational design of inhibitors. A structure-based comparison between PDFs reveals some conserved differences between type I and type II enzymes. Moreover, our structures provide insights into the known instability of PDF caused by oxidation of the metal-ligating cysteine residue.