FIG. 3.

Origins of replication of pAP1. (A) Alignment of the putative DSO with the known DSOs of pIJ101, pJV1, and pSN22 and homologous regions from pSB24.2 and pBL1. The underlined GG dinucleotide indicates the position of the nick site (22, 25). Residues are boxed where four or more sequences have identical amino acids. (B) Secondary structure of the putative SSO of pAP1 predicted by using the mfold program, version 2.3 (Micheal Zuker, Washington University, St. Louis, Mo.). The hexanucleotide sequence TCGCGT, which is similar to the ssi consensus sequence TAGCGT defined by Zaman et al. (26), is indicated by the asterisks.