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PDBsum entry 1wp9
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References listed in PDB file
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Key reference
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Title
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Crystal structure and functional implications of pyrococcus furiosus hef helicase domain involved in branched DNA processing.
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Authors
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T.Nishino,
K.Komori,
D.Tsuchiya,
Y.Ishino,
K.Morikawa.
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Ref.
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Structure, 2005,
13,
143-153.
[DOI no: ]
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PubMed id
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Abstract
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DNA and RNA frequently form various branched intermediates that are important
for the transmission of genetic information. Helicases play pivotal roles in the
processing of these transient intermediates during nucleic acid metabolism. The
archaeal Hef helicase/ nuclease is a representative protein that processes flap-
or fork-DNA structures, and, intriguingly, its C-terminal half belongs to the
XPF/Mus81 nuclease family. Here, we report the crystal structure of the helicase
domain of the Hef protein from Pyrococcus furiosus. The structure reveals a
novel helical insertion between the two conserved helicase core domains. This
positively charged extra region, structurally similar to the "thumb"
domain of DNA polymerase, plays critical roles in fork recognition. The Hef
helicase/nuclease exhibits sequence similarity to the Mph1 helicase from
Saccharomyces cerevisiae; XPF/Rad1, involved in DNA repair; and a putative Hef
homolog identified in mammals. Hence, our findings provide a structural basis
for the functional mechanisms of this helicase/nuclease family.
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Figure 6.
Figure 6. Models of Hef in Complex with Branched Structure
DNA
Hef is shown as the surface representation whose
orientation is the same as in Figure 1B. The surface was colored
according to its electrostatic surface potential at + or - 10 kB
T/e for positive (blue) or negative (red) charge potential by
using the program GRASP (Nicholls, 1993). DNA is shown as
schematic double helices.
(A) Model 1. Domain 2 interacts
with the double-stranded region of the branched structure, and
the fork-structured DNA is recognized by the coordinated action
of all three domains.
(B) Model 2. Domain 2 directly
interacts with a moiety near the junction, and the helicase core
domains support double- or single-stranded DNA binding in a mode
similar to the case of RecG.
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The above figure is
reprinted
by permission from Cell Press:
Structure
(2005,
13,
143-153)
copyright 2005.
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