Figure 6. Model for DNA end resection by the Sgs1‐RPA‐Dna2 complex.

Sgs1‐Dna2 complex binds first to a 5′ DNA overhang assisted by RPA. At the DNA junction, both helicases start to move unidirectionally on either of the strands. Due to the faster movement of Sgs1, this helicase powers the unwinding of the DNA duplex and causes the formation of a ssDNA loop in front of Dna2. Upon an occasional strand switch of Sgs1, the protein rewinds the DNA and moves toward Dna2. This leads to shortening of the loop. Upon encounter of Dna2, Sgs1 switches back to the original strand to power further unwinding.