Redox proteomics uncovers peroxynitrite-sensitive proteins that help Escherichia coli to overcome nitrosative stress
21.05.2013
Lindemann C, Lupilova N, Muller A, Warscheid B, Meyer HE, Kuhlmann K, Eisenacher M, Leichert LI.
J Biol Chem. 2013;288(27):19698-714
Peroxynitrite is a highly reactive chemical species with antibacterial properties that is synthesized in immune cells. In a proteomic approach, we identified specific target proteins of peroxynitrite-induced modifications in Escherichia coli. While peroxynitrite caused a fairly indiscriminate nitration of tyrosine residues, reversible modifications of protein thiols were highly specific. We used a quantitative redox-proteomic method based on isotope coded affinity tag (ICAT) chemistry and identified four proteins consistently thiol-modified in cells treated with peroxynitrite: AsnB, FrmA, MaeB, and RidA. All four were required for peroxynitrite stress tolerance in vivo. Three of the identified proteins were modified at highly conserved cysteines and MaeB and FrmA are known to be directly involved in the oxidative and nitrosative stress response in E. coli. In in vitro studies we could show that the activity of RidA, a recently discovered enamine/imine deaminase, is regulated in a specific manner by the modification of its single conserved cysteine. Mutation of this cysteine 107 to serine generated a constitutively active protein that was not susceptible to peroxynitrite.
