2p6r: Difference between revisions

Revision as of 19:26, 21 February 2008

Crystal structure of superfamily 2 helicase Hel308 in complex with unwound DNA

OverviewOverview

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.

About this StructureAbout this Structure

2P6R is a Protein complex structure of sequences from Archaeoglobus fulgidus. Full crystallographic information is available from OCA.

ReferenceReference

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

Page seeded by OCA on Thu Feb 21 18:26:26 2008

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OCA

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 ==Overview==
-To reveal the mechanism of processive strand separation by superfamily-2, (SF2) 3'--&gt;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'--&gt;5', helicases and reveal important mechanistic differences from SF1 helicases.
+To reveal the mechanism of processive strand separation by superfamily-2 (SF2) 3'--&gt;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'--&gt;5' helicases and reveal important mechanistic differences from SF1 helicases.
 ==About this Structure==
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 [[Category: Protein complex]]
 [[Category: Buettner, K.]]
-[[Category: Hopfner, K.P.]]
+[[Category: Hopfner, K P.]]
 [[Category: Nehring, S.]]
 [[Category: archaeal helicase]]
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 [[Category: sf2 helicase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 13:43:10 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:26:26 2008''