@article{6350d0b9201940c4b44b7eea70c19889,
title = "Mechanistic Basis for ATP-Dependent Inhibition of Glutamine Synthetase by Tabtoxinine-β-lactam",
abstract = "Tabtoxinine-β-lactam (TβL), also known as wildfire toxin, is a time- and ATP-dependent inhibitor of glutamine synthetase produced by plant pathogenic strains of Pseudomonas syringae. Here we demonstrate that recombinant glutamine synthetase from Escherichia coli phosphorylates the C3-hydroxyl group of the TβL 3-(S)-hydroxy-β-lactam (3-HβL) warhead. Phosphorylation of TβL generates a stable, noncovalent enzyme-ADP-inhibitor complex that resembles the glutamine synthetase tetrahedral transition state. The TβL β-lactam ring remains intact during enzyme inhibition, making TβL mechanistically distinct from traditional β-lactam antibiotics such as penicillin. Our findings could enable the design of new 3-HβL transition state inhibitors targeting enzymes in the ATP-dependent carboxylate-amine ligase superfamily with broad therapeutic potential in many disease areas.",
author = "Patrick, {Garrett J.} and Luting Fang and Jacob Schaefer and Sukrit Singh and Bowman, {Gregory R.} and Wencewicz, {Timothy A.}",
note = "Funding Information: We thank A. D{\textquoteright}Avignon (formerly at Department of Chemistry, Washington University in St. Louis; currently at Sanford Burnham Medical Research Institute, Orlando, FL), J. Kao (Department of Chemistry, Washington University in St. Louis), and B. Marsden (Department of Chemistry, Washington University in St. Louis) for assistance in the acquisition of solution NMR spectra. We thank Dr. Brad Evans at the Proteomics & Mass Spectrometry Facility at the Donald Danforth Plant Science Center (St. Louis, MO) for assistance with the acquisition of the QTRAP LC−MS/MS spectra (supported by the National Science Foundation under Grant DBI-0521250). We thank Margaret Reck (Department of Chemistry, Washington University in St. Louis) for assistance purifying tabtoxin from P. syringae cultures. We thank Dr. Joe Jez and Cynthia Holland (Department of Biology, Washington University in St. Louis) for diligent efforts crystallizing GS and analyzing diffraction patterns at the Advanced Photon Source at Argonne National Laboratory. Funding Information: *E-mail: wencewicz@wustl.edu. Phone: 314-935-7247. Fax: 314-935-6530. ORCID Jacob Schaefer: 0000-0002-7544-6408 Sukrit Singh: 0000-0003-1914-4955 Timothy A. Wencewicz: 0000-0002-5839-6672 Funding Research was supported by start-up funds from Washington University in St. Louis. Notes The authors declare no competing financial interest. Funding Information: We thank Dr. Brad Evans at the Proteomics & Mass Spectrometry Facility at the Donald Danforth Plant Science Center (St. Louis, MO) for assistance with the acquisition of the QTRAP LC-MS/MS spectra (supported by the National Science Foundation under Grant DBI-0521250). Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",
year = "2018",
month = jan,
day = "9",
doi = "10.1021/acs.biochem.7b00838",
language = "English",
volume = "57",
pages = "117--135",
journal = "Biochemistry",
issn = "0006-2960",
number = "1",
}