The pepN gene has been cloned into the multicopy plasmid pBR322. The restriction map of the insert was established and the gene was localized. By comparison with the restriction map of the plasmid pJP30 bearing the ompF region, it has been possible to order the ompF, asnS, and pepN genes. The ompF and asnS genes are contiguous and pepN is separated from asnS by a DNA fragment of about 1.6 kb.