Figure 4

Substrate topology and att site specificity. (A) Comparison of intermolecular integration reactions between supercoiled attP (pRJ2214) and linear attB (100 bp, threefold molar excess over attP) and between supercoiled attB (pRJ2215) and linear attP (100 bp, threefold molar excess over attB) substrates. (B) Comparison of intramolecular attP×attB deletion reactions (pBCPB-A1+) and intermolecular integration reactions between supercoiled attP (pRJ2214) and linear attB. (C) Comparison of intramolecular attP×attB deletion reactions on supercoiled and linear pBCPB-A1+. (D) Comparison of intramolecular attP×attB deletion (pBCPB-A1+) and inversion (pRJ2799) reactions. These two supercoiled substrates are identical except for the relative orientation of att sites. (E) Intermolecular integration reactions (40 minutes) between supercoiled attP (pRJ2214) and 100 bp linear fragments containing different att sites at threefold molar excess over attP. (F) Intermolecular integration reactions (40 minutes) between supercoiled attB (pRJ2214) and 100 bp linear fragments containing different att sites at threefold molar excess over attB. (G) Intermolecular integration reactions between supercoiled attP from phage U153 (pRJ2289) and 100 bp linear fragments containing the attB site that is used by both phages. (H) Sequence of the A118 and U153 attP sites. Non-identities on the P’ sides are highlighted with dots, and the three central nucleotides in common with attB are underlined.