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PDBsum entry 4blr
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References listed in PDB file
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Key reference
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Title
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Tracking in atomic detail the functional specializations in viral reca helicases that occur during evolution.
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Authors
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K.El omari,
C.Meier,
D.Kainov,
G.Sutton,
J.M.Grimes,
M.M.Poranen,
D.H.Bamford,
R.Tuma,
D.I.Stuart,
E.J.Mancini.
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Ref.
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Nucleic Acids Res, 2013,
41,
9396-9410.
[DOI no: ]
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PubMed id
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Abstract
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Many complex viruses package their genomes into empty protein shells and
bacteriophages of the Cystoviridae family provide some of the simplest models
for this. The cystoviral hexameric NTPase, P4, uses chemical energy to
translocate single-stranded RNA genomic precursors into the procapsid. We
previously dissected the mechanism of RNA translocation for one such phage, 12,
and have now investigated three further highly divergent, cystoviral P4 NTPases
(from 6, 8 and 13). High-resolution crystal structures of the set of P4s allow a
structure-based phylogenetic analysis, which reveals that these proteins form a
distinct subfamily of the RecA-type ATPases. Although the proteins share a
common catalytic core, they have different specificities and control mechanisms,
which we map onto divergent N- and C-terminal domains. Thus, the RNA loading and
tight coupling of NTPase activity with RNA translocation in 8 P4 is due to a
remarkable C-terminal structure, which wraps right around the outside of the
molecule to insert into the central hole where RNA binds to coupled L1 and L2
loops, whereas in 12 P4, a C-terminal residue, serine 282, forms a specific
hydrogen bond to the N7 of purines ring to confer purine specificity for the 12
enzyme.
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