Fig 9.

Alignment of integrase binding sites from other site-specific recombination systems, which are denoted with arrows. The “0” shown at the top of the figure represents the central base in the crossover region, with bases to the right indicated by positive numbers and bases to the left denoted with negative numbers. The arrows represent integrase binding sites. The core-type sites are inverted repeats that flank position 0. The numbering and spacing are approximate, and binding sites are not drawn to scale. The P6 and P7 arm-type sites from the mycobacteriophage L5 system are not included in the figure.