Fig. 3. Chimeric att-sites: organization and nomenclature.

(A) Overview of parental and hybrid att-site structure. Serine integrase att-sites consist of a dinucleotide core (black bar) that is flanked by two half-sites. Checkered patterns are used here to indicate attB half-sites; solid colors are used for attP. Drawings are not to scale. See the text for an explanation of our hybrid att-site naming system. (B) Detailed overview of parental and hybrid attB seqences. Mismatches in the B0–B3 and B0–B6 alignments are underlined. CbC B0 and TcT B0 are equivalent to the phiC31 and TG1 attB sites, respectively. (C) Detailed overview of parental and hybrid attP seqences. Mismatches in the P0–P3 and P0–P6 alignments are underlined. CbC P0 and TcT P0 are equivalent to the phiC31 and TG1 attP sites, respectively. In (B) and (C), only a central 26 nucleotide window is shown; see supplementary material Table S2 for the full sequences of all att-sites used in our study.