Fig. 2.

Pathways for the resolution of dHJ structures. a Proposed pathway for dHJ dissolution. In this pathway, BLM migrates the two HJs towards each other, then Topo IIIα decatenates the structure in the second step, producing exclusively non-crossover products. b Pathway for HJ resolvases. In this pathway, each HJ is cleaved by an HJ resolvase and an equal mixture of non-crossover and crossover products result, depending on if the HJs are cleaved symmetrically or asymmetrically, as depicted by the arrows