THE NUCLEOTIDE SEQUENCE OF cea AND THE REGION OF ORIGIN OF PLASMID pKY-1

Abstract

We have constructed a restriction map of the colicinogenic plasmid pKY-1 and analyzed its genetic structure. Although the cleavage map of pKY-1 is completely different from that of ColE1, the arrangement of its genes cea and imm and the region of origin (replication origin) is the same as that of ColE1. The nucleotide sequence of the region of origin and of the cea, imm and kil genes was determined. The sequence of the region of origin is almost identical with that of ColE1. The sequence of the RNAI deduced from the sequence is a hybrid of ColE1 and CloDF13 consistent with the fact that pKY-1 is compatible with ColE1. The amino acid sequence of colicin E1 deduced from the nucleotide sequence is almost identical with that of colicin E1. However, significant substitutions of amino acids in colicin E1 were observed in the region which would correspond to the N-M junction of colicin E1.