Multivalent translational control of transcription termination at attenuator of ilvGEDA operon of Escherichia coli K-12.

The regulatory region for the ilvGEDA operon of Escherichia coli K-12 has been located and characterized. ilv leader RNA transcribed from this region is described, and the DNA sequence of the region is presented. This DNA sequence contains a transcription promoter, a region coding for a 32-amino-acid polypeptide containing multiple isoleucine, valine, and leucine codons, and a transcription termination site preceding the first structural gene. The mutually exclusive secondary structures of the leader RNA have been analyzed. On the basis of these data, a model for the multivalent attenuation of the ilvGEDA operon is proposed.