Identification of 4-amino-4-deoxychorismate synthase as the molecular target for the antimicrobial action of (6s)-6-fluoroshikimate.
(6S)-6-Fluoroshikimate has antimicrobial activity. The molecular basis of this effect had not been identified, but there was speculation that (6S)-6-fluoroshikimate is first converted in vivo into 2-fluorochorismate, which then could inhibit 4-amino-4-deoxychorismate synthase (ADCS). 2-Fluorochorismate was prepared from E-fluorophosphoenolpyruvate and erythose-4-phosphate by the sequential reactions of DAHP synthase, dehydroquinate synthase, dehydroquinase, shikimate dehydrogenase, EPSP synthase, and chorismate synthase. Inhibition studies on ADCS showed that it was inhibited rapidly and irreversibly by 2-fluorochorismate. Electrospray mass spectrometry of the inactivated enzyme showed an additional mass of 198 +/- 10 Da. A novel peptide of 1087.6 Da was identified in the HPLC trace for the tryptic digest of 2-fluorochorismate-inactivated ADCS. Sequencing of this peptide by MS/MS showed that the peptide corresponded to residues 272-279 with a modification of 206.1 Da on Lys-274. This observation is particularly exciting in the context of a recent proposal for the catalytic mechanism of ADCS.
Department of Chemistry, University of Cambridge, University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.
Esther M M
EM
Bulloch
Michelle A
MA
Jones
Emily J
EJ
Parker
Andrew P
AP
Osborne
Elaine
E
Stephens
Gareth M
GM
Davies
John R
JR
Coggins
Chris
C
Abell
D000890:Anti-Infective Agents / Q000494:pharmacology*; D019731:Carbon-Nitrogen Ligases; D002827:Chorismic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D013058:Mass Spectrometry; D012765:Shikimic Acid / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D000637:Transaminases / Q000037:antagonists & inhibitors* / Q000378:metabolism
C492464:2-fluorochorismate; C087313:6-fluoroshikimic acid; D000890:Anti-Infective Agents; D004791:Enzyme Inhibitors; D012765:Shikimic Acid; D000637:Transaminases; C066599:aminodeoxychorismate synthase; D019731:Carbon-Nitrogen Ligases; D002827:Chorismic Acid