The nucleotide sequence surrounding the origin of DNA replication of Col E1

Abstract

The DNA of Col E₁ replicates from a unique origin located at a distance of 17–19% of the genome length from the single Eco R₁ cleavage site. The nucleotide sequence about this site has been determined by a combination of RNA and DNA sequencing techniques. The principal features of the sequence are two palindromes, one of which resembles a palindrome located in the intercistronic region of ØX174. The sequence also contains stretches of purine and pyrimidine clusters of the following compositions: pAT₅G, pC₂T₅G, pGT₅G. The origin sequence demonstrates that initiation of DNA replication takes place in an intercistronic region of Col E₁DNA, although the possibility that this region makes small polypeptides 30–40 residues long cannot be strictly eliminated at this time.