[Mutation slowing down the degradation of the beta beta'-subunits of Escherichia coli RNA-polymerase].

: The rpoC1 ts mutation affecting the RNA polymerase beta' subunit accelerates synthesis of RNA polymerase beta beta' subunits at 42 degrees C, while the surplus amount of subunits degrades in an hour's time. In a Ts strain with two RNA polymerase mutations, rpoC1 and rpoB251, we obtained a ts+ reversion designated opr24 which slows down degradation of surplus beta beta' subunits. The slowing down of degradation and the resulting accumulation of beta beta' subunits does not affect the kinetics of beta beta' subunit synthesis after the transfer to 42 degrees C. The effects of the opr24 are allele non-specific. The mutation also slows down degradation of beta' subunit and the amber fragment of beta subunit in the strain with subunit amber mutation rpoB22. Besides, the opr24 mutation reduces proteolysis of anomalous proteins containing canavanine. The opr24 mutation has been mapped between 17 and 21 minutes on the Escherichia coli map.