The replication origin region of Escherichia coli: nucleotide sequence and functional units.

The minichromosome pCM959 contains the DNA segment from bp -677 (left) to bp + 3335 (right) of the Escherichia coli replication origin, oriC. The nucleotide sequence of this plasmid was determined. The coding regions for proteins were identified, and the possible function of those proteins is discussed. Within oriC two extended systems of dyad symmetry were found, and their possible significance is considered.