Nucleotide sequence of the argF regulatory region of Escherichia coli K-12.

The deoxyribonucleotide sequence has been determined for the regulatory region of the arginine F gene (argF) of Escherichia coli K-12. The location of the argF coding region was deduced by comparison of the DNA sequence to the sequence predicted from the primary structure of the N-terminus of the argF gene product, the subunit of the "F" isoenzyme of ornithine transcarbamylase. Transcription of the argF gene was found to initiate at a position approx. 40 bp preceding the N-terminal codon for OTCase. Comparison of the region surrounding the origin of transcription with a computer-generated "model promoter sequence" revealed structural similarities between the two sequences, in particular, the promoter-associated stretches known as the "Pribnow box" and "minus 35 contact site". Another feature noted for the argF promoter region was its extreme abundance of A : T nucleotide pairs. In the region preceding the start site for argF translation, a sequence was observed to be complementary to the 3' end of the 16S RNA component of the E. coli ribosome. Both the length and the nucleotide sequence of the argF leader region indicate that the argF gene does not contain an attenuator proposed to exist in other operons concerned with amino acid biosynthesis.