Fig. 8: Cartoon model for E1 DNA unwinding.
From: Unwinding of a DNA replication fork by a hexameric viral helicase
Each arm of the RF DNA associates with specific protein segments indicated with the hands. OBD B tracks the major groove of the inbound, rotating, dsDNA while additional OBDs surround it, stabilising its position above the collar domain. OBD E and residues in the E1HD domain (Asn352) and inter-domain linker (Lys310) chaperone the 5′ ssDNA away from the unwinding point (see Fig. 5). Unwinding is driven by ATP hydrolysis in the AAA+ domain linked to translocation of the 3′ ssDNA. Strand separation could be assisted by a once-per-revolution power-stroke of the collar domain, directly coupled to the ATPase cycle.
