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PDBsum entry 1szp
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DNA binding protein
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PDB id
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1szp
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Contents |
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* Residue conservation analysis
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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 of a rad51 filament.
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Authors
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A.B.Conway,
T.W.Lynch,
Y.Zhang,
G.S.Fortin,
C.W.Fung,
L.S.Symington,
P.A.Rice.
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Ref.
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Nat Struct Mol Biol, 2004,
11,
791-796.
[DOI no: ]
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PubMed id
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Abstract
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Rad51, the major eukaryotic homologous recombinase, is important for the repair
of DNA damage and the maintenance of genomic diversity and stability. The active
form of this DNA-dependent ATPase is a helical filament within which the search
for homology and strand exchange occurs. Here we present the crystal structure
of a Saccharomyces cerevisiae Rad51 filament formed by a gain-of-function
mutant. This filament has a longer pitch than that seen in crystals of Rad51's
prokaryotic homolog RecA, and places the ATPase site directly at a new interface
between protomers. Although the filament exhibits approximate six-fold symmetry,
alternate protein-protein interfaces are slightly different, implying that the
functional unit of Rad51 within the filament may be a dimer. Additionally, we
show that mutation of His352, which lies at this new interface, markedly
disrupts DNA binding.
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Figure 2.
Figure 2. Filaments of Rad51 and RecA. (a) The Rad51 filament
found in these crystals has a helical pitch of 130 Å and is
composed of two crystallographically independent monomers
(yellow and green) that alternate to form a filament with exact
three-fold but only approximate six-fold screw symmetry. A
sulfate (black spheres) mimics the binding of phosphate in the
ATPase site, which is nestled directly at the interface between
two protomers (arrow). One of the N-terminal domains that line
the upper surface of the filament is circled. (b) The filament
formed in RecA crystals has a helical pitch of  83
Å and is shown with each crystallographically equivalent monomer
colored differently
(,
).
The structurally conserved ATPase
domains are in the same orientation relative to the filament
axis as in a. The crystallographically observed ADP is in
ball-and-stick form, positioned a substantial distance from the
adjacent protomer. The C-terminal domains (circled) line the
lower surface of the filament.
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Figure 3.
Figure 3. Oligomerization of Rad51. (a) The Rad51 filament
assembles by packing a  -strand
from the interdomain linker of one protomer (green) onto the
central sheet of the adjacent monomer (yellow). Interactions
between ATPase domains include a helix (purple) that is
disordered in nonfilament structures of RadA and Rad51. (b) A
peptide from BRCA2 (orange) bound to the human Rad51 ATPase
domain (yellow)
().
The peptide mimics the -strand
interaction motif of intact Rad51. The loop following the
disordered helix is purple.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
Nat Struct Mol Biol
(2004,
11,
791-796)
copyright 2004.
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