Affiliation:
1. British Biotech Pharmaceuticals Ltd., Oxford OX4 6LY,1 and
2. Naeja Pharmaceutical, Inc., Edmonton, Alberta T6E 5V2, Canada2
3. Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN,3 United Kingdom, and
Abstract
ABSTRACT
Peptide deformylase (PDF) is an essential bacterial metalloenzyme which deformylates the
N
-formylmethionine of newly synthesized polypeptides and as such represents a novel target for antibacterial chemotherapy. To identify novel PDF inhibitors, we screened a metalloenzyme inhibitor library and identified an
N
-formyl-hydroxylamine derivative, BB-3497, and a related natural hydroxamic acid antibiotic, actinonin, as potent and selective inhibitors of PDF. To elucidate the interactions that contribute to the binding affinity of these inhibitors, we determined the crystal structures of BB-3497 and actinonin bound to
Escherichia coli
PDF at resolutions of 2.1 and 1.75 Å, respectively. In both complexes, the active-site metal atom was pentacoordinated by the side chains of Cys 90, His 132, and His 136 and the two oxygen atoms of
N
-formyl-hydroxylamine or hydroxamate. BB-3497 had activity against gram-positive bacteria, including methicillin-resistant
Staphylococcus aureus
and vancomycin-resistant
Enterococcus faecalis
, and activity against some gram-negative bacteria. Time-kill analysis showed that the mode of action of BB-3497 was primarily bacteriostatic. The mechanism of resistance was via mutations within the formyltransferase gene, as previously described for actinonin. While actinonin and its derivatives have not been used clinically because of their poor pharmacokinetic properties, BB-3497 was shown to be orally bioavailable. A single oral dose of BB-3497 given 1 h after intraperitoneal injection of
S. aureus
Smith or methicillin-resistant
S. aureus
protected mice from infection with median effective doses of 8 and 14 mg/kg of body weight, respectively. These data validate PDF as a novel target for the design of a new generation of antibacterial agents.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
210 articles.
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