Fig. 6.

Schematic summary of the Int bridges in integrative and excisive recombination. The middle panel diagrams the Int bridges of the Holliday junction recombination intermediates determined in this study. In the integrative complex, all four core sites and four of the five arm sites enjoy an Int bridge, whereas the excisive complex engages three of the four core sites and three of the five arm sites. The flanking panels (brackets) depict extrapolations from the HJ complexes to the respective att site recombination partners (substrates) and recombinants (products) based on the deduction that Int bridges are not broken and reformed during recombination (Discussion).