Sequence of the promoter and 5′ coding region of pepN, and the amino-terminus of peptidase N from Escherichia coli K-12

Summary

The pepN gene of Escherichia coli K-12 has been cloned onto a multi-copy plasmid and shown to encode a polypeptide which co-migrates with purified peptidase N. Transformed strains have been shown to contain up to a one hundred fold increase in the amount of peptidase N. We isolated the peptidase N protein and determined the sequence of its first 15 amino acids. By restriction mapping, we identified and subcloned the 5′ region of the pepN gene and then determined its nucleotide sequence. Comparison of the actual amino acid sequence with that predicted from the extended open reading frame found in the DNA sequence indicated that peptidase N is not synthesized as a pre-protein precursor. The presumed region preceding the open reading frame contained nucleotide sequence having homology to the procaryotic promoter consensus sequences for the -35 and the -10 regions and the ribosome binding site.