The E. coli origin, oriC, contains: four 9-base-pair consensus sequences. three AT-rich direct repeats. eleven GATC sites. four 9-base-pair consensus sequences and three AT-rich direct repeats. four 9-base-pair consensus sequences, three AT-rich direct repeats, and eleven GATC sites.

Four 9-base-pair consensus sequences and three AT-rich direct repeats.

Explanation:

The E. coli origin, oriC is ~ 245 base pair (bp) long. Within this ~ 245 bp DNA stretch, it contains (1) Four 9-base-pair consensus sequences which has nucleotide arrangement TTATCCACA and (2) three AT-rich direct repeats which has GATCTNTTN nucleotide arrangement. Both of these types of DNA sequences serve different functions in DNA replication which are mentioned as under:

(1) Four 9-base-pair consensus sequences (TTATCCACA):

4 TTATCCACA consensus sequences serve the purpose of binding site for replication initiator which is DnaA.ATP or Dna A protein in case of prokaryotes like E. coli.

(2) Three AT-rich direct repeats consensus sequences (GATCTNTTN):

It comprises, 3 repeats of a 13 base pair (bp) sequence which is  GATCTNTTN. These tandem repeats serve the purpose of DNA unwinding element (DUE). These sequences are AT rich which are recognized by replication initiator so as to denature the DNA. As soon as the DNA gets denatured, replication initiation occurs.