Protection from superoxide damage associated with an increased level of the YggX protein in Salmonella enterica

doi:10.1073/pnas.151243198

Protection from superoxide damage associated with an increased level of the YggX protein in Salmonella enterica

Jeffrey Gralnick and
Diana Downs†

Department of Bacteriology, University of Wisconsin, Madison, WI 53706

Communicated by John R. Roth, University of Utah, Salt Lake City, UT (received for review September 27, 2000)

Abstract

The deleterious effect of superoxide radicals on cell growth and survival is predominately caused by rapid oxidation of labile [Fe-S] clusters in proteins. Oxidation of these clusters releases Fe(II) ions, which participate in Fenton chemistry that damages DNA. Here it is shown that elevated levels of the YggX protein increase the resistance of Salmonella enterica to superoxide stress, reverse enzymatic defects attributed to oxidized [Fe-S] clusters, and decrease the spontaneous mutation frequency. The data are consistent with a model in which YggX protects protein [Fe-S] clusters from oxidation.

Footnotes

↵ † To whom reprint requests should be addressed at: University of Wisconsin, 1550 Linden Drive, Madison, WI 53706. E-mail: downs{at}bact.wisc.edu.
Abbreviations:

Acn,

aconitase;

SOD,

superoxide dismutase;

GSH,

glutathione;

PQ,

paraquat, MNNG, N-methyl-N′-nitro-N-nitrosoguanidine