Construction and characterization of glutaredoxin-negative mutants of Escherichia coli.
AUTOR(ES)
Russel, M
RESUMO
Deoxyribonucleotides, the precursors of DNA, are formed de novo by ribonucleotide reductase, and in vitro thioredoxin or glutathione plus glutaredoxin have been isolated as hydrogen donors. The in vivo hydrogen donor for ribonucleotide reductase is not known. To study this, the Escherichia coli glutaredoxin gene (255 base pairs) was inactivated by inserting a 2-kilobase kanamycin-resistance fragment into the coding sequence of the cloned gene. The inactivated gene was inserted into the E. coli chromosome and mapped to about 18.5 min. A gene replacement technique was used to obtain a strain, A407, that lacked glutaredoxin by radioimmunoassay and by enzymatic assay with ribonucleotide reductase. Glutaredoxin was found not to be essential for viability of E. coli. Thioredoxin is also not essential for viability, as had been shown earlier, but a double mutant lacking glutaredoxin and thioredoxin could not be obtained by P1 transduction on a defined medium, indicating that either thioredoxin or glutaredoxin is essential. In rich medium, very slowly growing, unstable transductants were obtained that at high frequency gave rise to better growing cells. One such isolate, A410, was shown to still lack glutaredoxin and thioredoxin.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=279686Documentos Relacionados
- Isolation and characterization of isoprene mutants of Escherichia coli.
- Isolation and characterization of enterotoxin-deficient mutants of Escherichia coli.
- Isolation and characterization of dnaJ null mutants of Escherichia coli.
- Isolation and characterization of conditional-lethal rho mutants of Escherichia coli.
- Characterization of cold-sensitive secY mutants of Escherichia coli.