Regulation of yodA encoding a novel cadmium-induced protein in Escherichia coli The GenBank accession number for the E. coli yodA gene and the SWISS-PROT accession number for E. coli YodA protein in this paper are AAC75039 and P76344, respectively.

Abstract

Bacterial accommodation to moderate concentrations of cadmium is accompanied by transient activation of general stress proteins as well as a sustained induction of other proteins of hitherto unknown functions. One of the latter proteins was previously identified as the product of the Escherichia coli yodA ORF. The yodA ORF encodes 216 aa residues (the YodA protein) and the increased synthesis of YodA during cadmium stress was found probably to be a result of transcriptional activation from one single promoter upstream of the structural yodA gene. Analysis of a transcriptional gene fusion, P yodA -lacZ, demonstrated that basal expression of yodA is low during exponential growth and expression is increased greater than 50-fold by addition of cadmium to growing cells. However, challenging cells with additional metals such as zinc, copper, cobalt and nickel did not increase the level of yodA expression. In addition, hydrogen peroxide also increased yodA expression whereas the superoxide-generating agent paraquat failed to do so. Surprisingly, cadmiuminduced transcription of yodA is dependent on soxS and fur, but independent of oxyR. Moreover, a double relA spoT mutation abolished induction of yodA during cadmium exposure but ppGpp is not sufficient to induce yodA since expression of the gene is not elevated during stationary phase. After 45 min of cadmium exposure the YodA protein was primarily detected in the cytoplasmic fraction but was later (150 min) found in both the cytoplasmic and periplasmic compartments.

SoxS Increases the Expression of the Zinc Uptake System ZnuACB in an Escherichia coli Murine Pyelonephritis Model

“…These findings show that znuCB expression is enhanced by SoxS. In this regard, SoxS has been shown to affect the expression of other zinc transport factors during cobalt stress (40). Our findings also agree with a study that showed increased expression of members of the soxS regulon in response to low extracellular Zn 2ϩ concentrations in vitro (48).…”

Type 2 Secretion Promotes Enterohemorrhagic Escherichia coli Adherence and Intestinal Colonization

“…The Z3065 protein is 99% identical to YodA from E. coli K-12, and the Z3065 gene and yodA are flanked by the same genes in their respective genomes. In E. coli K-12, YodA (recently renamed ZinT [24]) is a metal-binding protein that is secreted into the periplasm under stress conditions (6,40).…”

“…YodA was originally identified as a (40). The YodA crystal structure revealed that this protein binds to metal ions, including cadmium and zinc, and is structurally related to the lipocalin family of proteins (7).…”

YodA from Escherichia coli Is a Metal-binding, Lipocalin-like Protein

“…The response of microorganisms to heavy metals, such as mercury and cadmium, has been studied in some detail (1,(7)(8)(9)(10)(11)(12). The toxic elements are primarily removed by active transport, reducing their intracellular concentration to acceptable levels (13).…”