Peptide aldehyde inhibitors of bacterial peptide deformylases.
Bacterial peptide deformylases (PDF, EC 3.5.1.27) are metalloenzymes that cleave the N-formyl groups from N-blocked methionine polypeptides. Peptide aldehydes containing a methional or norleucinal inhibited recombinant peptide deformylase from gram-negative Escherichia coli and gram-positive Bacillus subtilis. The most potent inhibitor was calpeptin, N-CBZ-Leu-norleucinal, which was a competitive inhibitor of the zinc-containing metalloenzymes, E. coli and B. subtilis PDF with Ki values of 26.0 and 55.6 microM, respectively. Cobalt-substituted E. coli and B. subtilis deformylases were also inhibited by these aldehydes with Ki values for calpeptin of 9.5 and 12.4 microM, respectively. Distinct spectral changes were observed upon binding of calpeptin to the Co(II)-deformylases, consistent with the noncovalent binding of the inhibitor rather than the formation of a covalent complex. In contrast, the chelator 1,10-phenanthroline caused the time-dependent inhibition of B. subtilis Co(II)-PDF activity with the loss of the active site metal. The fact that calpeptin was nearly equipotent against deformylases from both gram-negative and gram-positive bacterial sources lends further support to the idea that a single deformylase inhibitor might have broad-spectrum antibacterial activity.
Department of Enzymology, Merck Research Laboratories, Rahway, New Jersey, 07065, USA.
D J
DJ
Durand
B
B
Gordon Green
J F
JF
O'Connell
S K
SK
Grant
D000447:Aldehydes / Q000378:metabolism*; D000581:Amidohydrolases; D000626:Aminopeptidases / Q000037:antagonists & inhibitors*; D001412:Bacillus subtilis / Q000201:enzymology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000201:enzymology*; D020128:Inhibitory Concentration 50; D007700:Kinetics; D008956:Models, Chemical
D000447:Aldehydes; D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; C071482:calpeptin; D000626:Aminopeptidases; D000581:Amidohydrolases; C084507:peptide deformylase