2p6r
Crystal structure of superfamily 2 helicase Hel308 in complex with unwound DNACrystal structure of superfamily 2 helicase Hel308 in complex with unwound DNA
Structural highlights
Evolutionary Conservation![]() Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTo 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. Structural basis for DNA duplex separation by a superfamily-2 helicase.,Buttner K, Nehring S, Hopfner KP Nat Struct Mol Biol. 2007 Jul;14(7):647-52. Epub 2007 Jun 10. PMID:17558417[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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