Linkage between catecholate siderophores and the multicopper oxidase CueO in Escherichia coli.
The multicopper oxidase CueO had previously been demonstrated to exhibit phenoloxidase activity and was implicated in intrinsic copper resistance in Escherichia coli. Catecholates can potentially reduce Cu(II) to the prooxidant Cu(I). In this report we provide evidence that CueO protects E. coli cells by oxidizing enterobactin, the catechol iron siderophore of E. coli, in the presence of copper. In vitro, a mixture of enterobactin and copper was toxic for E. coli cells, but the addition of purified CueO led to their survival. Deletion of fur resulted in copper hypersensitivity that was alleviated by additional deletion of entC, preventing synthesis of enterobactin. In addition, copper added together with 2,3-dihydroxybenzoic acid or enterobactin was able to induce a Phi(cueO-lacZ) operon fusion more efficiently than copper alone. The reaction product of the 2,3-dihydroxybenzoic acid oxidation by CueO that can complex Cu(II) ions was determined by gas chromatography-mass spectroscopy and identified as 2-carboxymuconate.
Department of Soil, Water, and Environmental Science, University of Arizona, Shantz Bldg. #38, Rm. 424, Tucson, AZ 85721, USA.
Gregor
G
Grass
Keshari
K
Thakali
Phillip E
PE
Klebba
Daniel
D
Thieme
Axel
A
Müller
Günter F
GF
Wildner
Christopher
C
Rensing
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D003300:Copper / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000502:physiology; D004758:Enterobactin / Q000378:metabolism / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics / Q000502:physiology; D017930:Genes, Reporter; D062385:Hydroxybenzoates / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D017262:Siderophores / Q000378:metabolism*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D062385:Hydroxybenzoates; D012097:Repressor Proteins; D017262:Siderophores; C068477:ferric uptake regulating proteins, bacterial; D004758:Enterobactin; C009135:2,3-dihydroxybenzoic acid; D003300:Copper; D010088:Oxidoreductases; C499679:cueO protein, E coli; D001616:beta-Galactosidase