It contains four regions (A, B1, B2, and B3), named in order of their effect on plasmid stability.
Element A is highly conserved, consisting of the consensus sequence: 5'- T/A T T T A Y R T T T T/A -3'(where Y is either pyrimidine and R is either purine).
As seen above the ARS are considerably A-T rich which makes it easy for replicative proteins to disrupt the H-bonding in that area.
Melting of DNA occurs within domain B2, induced by attachment of ARS binding factor 1 to B3.
If the genome fragment contained an origin of replication, cells were able to grow in a medium lacking histidine.