Enzymatic reduction of mercurous ions in Escherichia coli bearing R factor.

Removal of nickel and total chromium using Escherichia coli biofilm supported on clinoptilolite

-Biofilm is communities of microorganisms attached to the surface and is able to concentrate metal species within their cell structure. Therefore, the aim of this study was to produce Escherichia coli biofilm on zeolite (clinoptilolite) and evaluate its ability for nickel (Ni) and chromium (Cr) adsorption from aqueous solutions. A laboratory-scale batch model was used for biodsorption assay. Th...

Urease of enterohemorrhagic Escherichia coli: evidence for regulation by fur and a trans-acting factor.

Recent genomic analyses of Escherichia coli O157:H7 strain EDL933 revealed two loci encoding urease gene homologues (ureDABCEFG), which are absent in nonpathogenic E. coli strain K-12. This report demonstrates that the cloned EDL933 ure gene cluster is capable of synthesizing urease in an E. coli DH5alpha background. However, when the gene fragment is transformed back into the native EDL933 bac...

Enzymatic regulation of the radical content of the small subunit of Escherichia coli ribonucleotide reductase involving reduction of its redox centers.

The active form of protein B2, a homodimeric subunit of Escherichia coli ribonucleotide reductase, contains a diferric iron center and a cationic free radical localized to tyrosine 122 of one of the two polypeptide chains. Hydroxyurea scavenges this radical but leaves the iron center intact. The resulting metB2 (earlier named B2/HU) is enzymatically inactive. Crude extracts of E. coli catalyze ...

Comparison of T7- and Lac-Based Systems for the Periplasmic Expression of Human Granulocyte Macrophage Colony Stimulating Factor in Escherichia coli

Enhancement of Solubility and Specific Activity of a Cu/Zn Superoxide Dismutase by Co-expression with a Copper Chaperone in Escherichia coli

Background: Human Cu/Zn superoxide dismutase (hSOD1) is an antioxidant enzyme with potential as a therapeutic agent. However, heterologous expression of hSOD1 has remained an issue due to Cu2+ insufficiency at protein active site, leading to low solubility and enzymatic activity.Objectives:The effect of co-expressed human copper chaperone (hCCS) to enhance the solubility and enzymatic act...