Genetic studies on the beta subunit of Escherichia coli RNA polymerase. IX. The role of the carboxy-terminus in enzyme assembly.

The assembly of RNA polymerase was studied in Escherichia coli mutants encoding large N-terminal amber fragments of the beta subunit. Whereas the removal of up to 20% of the carboxy-terminus does not prevent the formation of premature core enzyme, the amber fragments seem to interfere with holoenzyme production. These studies permit, therefore, the localization of a region on the beta polypeptide involved in sigma binding.