Spontaneously-occurring rifampicin-resistant mutants that survive on low (20 micrograms ml-1) but not high drug concentrations (200 micrograms ml-1) have been isolated. One such mutation appears to map close to residue 650 on the beta structural gene. RNA polymerase from low-level resistant strains
Genetic studies on the β subunit of Escherichia coli RNA polymerase
✍ Scribed by Nene, Vishvanath ;Glass, Robert E.
- Publisher
- Springer
- Year
- 1984
- Tongue
- English
- Weight
- 713 KB
- Volume
- 194
- Category
- Article
- ISSN
- 0026-8925
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✦ Synopsis
We have isolated a set of strains that synthesise 331 potential variants of E. coli DNA-dependent RNA polymerase making use of nonsense suppression of amber mutations in the beta structural gene; rpoB. Translational mapping, together with the effect of known amino acid substitutions, has allowed us to locate sites on the beta polypeptide involved in transcription termination, stringent response and resistance to the antibiotic rifampicin. In general, the C-terminal quarter appears to be less affected by such single amino acid exchanges than the rest of beta. These studies permit for the first time structure-function correlates for the beta subunit of RNA polymerase.
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