Glutathione and transition-metal homeostasis in Escherichia coli.
Glutathione (GSH) and its derivative phytochelatin are important binding factors in transition-metal homeostasis in many eukaryotes. Here, we demonstrate that GSH is also involved in chromate, Zn(II), Cd(II), and Cu(II) homeostasis and resistance in Escherichia coli. While the loss of the ability to synthesize GSH influenced metal tolerance in wild-type cells only slightly, GSH was important for residual metal resistance in cells without metal efflux systems. In mutant cells without the P-type ATPase ZntA, the additional deletion of the GSH biosynthesis system led to a strong decrease in resistance to Cd(II) and Zn(II). Likewise, in mutant cells without the P-type ATPase CopA, the removal of GSH led to a strong decrease of Cu(II) resistance. The precursor of GSH, gamma-glutamylcysteine (gammaEC), was not able to compensate for a lack of GSH. On the contrary, gammaEC-containing cells were less copper and cadmium tolerant than cells that contained neither gammaEC nor GSH. Thus, GSH may play an important role in trace-element metabolism not only in higher organisms but also in bacteria.
Institute for Biology, Life Science Faculty, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str 3, 06099 Halle, Germany.
Kerstin
K
Helbig
Corinna
C
Bleuel
Gerd J
GJ
Krauss
Dietrich H
DH
Nies
D000251:Adenosine Triphosphatases / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D002104:Cadmium / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D004151:Dipeptides / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000737:chemistry / Q000254:growth & development / Q000502:physiology*; D017353:Gene Deletion; D005978:Glutathione / Q000378:metabolism*; D006706:Homeostasis; D019216:Metals, Heavy / Q000378:metabolism / Q000494:pharmacology; D016254:Mutagenesis, Insertional; D013438:Sulfhydryl Compounds / Q000032:analysis; D015032:Zinc / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D004151:Dipeptides; D019216:Metals, Heavy; D013438:Sulfhydryl Compounds; D002104:Cadmium; D003300:Copper; D000251:Adenosine Triphosphatases; C109898:Zn(II)-translocating P-type ATPase; D005978:Glutathione; D015032:Zinc; C017341:gamma-glutamylcysteine