Characterization of an iron sensitive Mud1 mutant inE. colilacking the ribonucleotide reductase subunit B2
✍ Scribed by Klaus Hantke
- Book ID
- 104763192
- Publisher
- Springer
- Year
- 1988
- Tongue
- English
- Weight
- 787 KB
- Volume
- 149
- Category
- Article
- ISSN
- 0302-8933
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✦ Synopsis
The mutant, generated by a Mudl insertion, formed long non-viable filaments in the presence of iron and air. Under anaerobic conditions normal growth in the presence of iron was observed. The mutation was mapped by PI transductions at 48 rain on the genetic map of Escherichia coli. By Southern blotting the insertion point was determined to be in nrdB, the structural gene for the ribonucleotide reductase subunit B2. The mutation could be complemented by the cloned nrdB gene. Up to now it was assumed that E. coli possesses only one enzyme for the synthesis of deoxyribonucleotides and only conditional lethal (temperature sensitive) mutants were isolated in nrdB. The insertion of Mud1 in nrdB should lead to a complete loss of the essential B2 subunit. Since the strain was able to grow under anaerobic conditions on minimal medium lacking deoxyribonucleotides an additional pathway for the synthesis of deoxyribonucleotides is postulated.