Peptide deformylase inhibitors as potent antimycobacterial agents.
Peptide deformylase (PDF) catalyzes the hydrolytic removal of the N-terminal formyl group from nascent proteins. This is an essential step in bacterial protein synthesis, making PDF an attractive target for antibacterial drug development. Essentiality of the def gene, encoding PDF from Mycobacterium tuberculosis, was demonstrated through genetic knockout experiments with Mycobacterium bovis BCG. PDF from M. tuberculosis strain H37Rv was cloned, expressed, and purified as an N-terminal histidine-tagged recombinant protein in Escherichia coli. A novel class of PDF inhibitors (PDF-I), the N-alkyl urea hydroxamic acids, were synthesized and evaluated for their activities against the M. tuberculosis PDF enzyme as well as their antimycobacterial effects. Several compounds from the new class had 50% inhibitory concentration (IC50) values of <100 nM. Some of the PDF-I displayed antibacterial activity against M. tuberculosis, including MDR strains with MIC90 values of <1 microM. Pharmacokinetic studies of potential leads showed that the compounds were orally bioavailable. Spontaneous resistance towards these inhibitors arose at a frequency of < or =5 x 10(-7) in M. bovis BCG. DNA sequence analysis of several spontaneous PDF-I-resistant mutants revealed that half of the mutants had acquired point mutations in their formyl methyltransferase gene (fmt), which formylated Met-tRNA. The results from this study validate M. tuberculosis PDF as a drug target and suggest that this class of compounds have the potential to be developed as novel antimycobacterial agents.
Teo
Jeanette W P
JW
Novartis Institute for Tropical Diseases, 10 Biopolis Road, 05-01 Chromos, Singapore 138670, Republic of Singapore.
Thayalan
Pamela
P
Beer
David
D
Yap
Amelia S L
AS
Nanjundappa
Mahesh
M
Ngew
Xinyi
X
Duraiswamy
Jeyaraj
J
Liung
Sarah
S
Dartois
Veronique
V
Schreiber
Mark
M
Hasan
Samiul
S
Cynamon
Michael
M
Ryder
Neil S
NS
Yang
Xia
X
Weidmann
Beat
B
Bracken
Kathryn
K
Dick
Thomas
T
Mukherjee
Kakoli
K
D000284:Administration, Oral; D000581:Amidohydrolases / Q000037:antagonists & inhibitors*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics; D015139:Blotting, Southern; D002021:Buffers; D003470:Culture Media; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000235:genetics; D030541:Databases, Genetic; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D005260:Female; D007275:Injections, Intravenous; D051379:Mice; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000187:drug effects* / Q000235:genetics; D009163:Mycobacterium bovis / Q000187:drug effects / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011480:Protease Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D002021:Buffers; D003470:Culture Media; D004269:DNA, Bacterial; D011480:Protease Inhibitors; D000581:Amidohydrolases; C084507:peptide deformylase