Summary information and primary citation
- PDB-id
- 2p6r; SNAP-derived features in text and JSON formats;
DNAproDB
- Class
- DNA binding protein-DNA
- Method
- X-ray (3.0 Å)
- Summary
- Crystal structure of superfamily 2 helicase hel308 in complex with unwound DNA
- Reference
- Buttner K, Nehring S, Hopfner KP (2007): "Structural basis for DNA duplex separation by a superfamily-2 helicase." Nat.Struct.Mol.Biol., 14, 647-652. doi: 10.1038/nsmb1246.
- Abstract
- To reveal the mechanism of processive strand separation by superfamily-2 (SF2) 3'-->5' helicases, we determined apo and DNA-bound crystal structures of archaeal Hel308, a helicase that unwinds lagging strands and is related to human DNA polymerase theta. Our structure captures the duplex-unwinding reaction, shows that initial strand separation does not require ATP and identifies a prominent beta-hairpin loop as the unwinding element. Similar loops in hepatitis C virus NS3 helicase and RNA-decay factors support the idea that this duplex-unwinding mechanism is applicable to a broad subset of SF2 helicases. Comparison with ATP-bound SF2 enzymes suggests that ATP promotes processive unwinding of 1 base pair by ratchet-like transport of the 3' product strand. Our results provide a first structural framework for strand separation by processive SF2 3'-->5' helicases and reveal important mechanistic differences from SF1 helicases.
