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PDBsum entry 2grw
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References listed in PDB file
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Key reference
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Title
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Breaking pseudo-Twofold symmetry in the poliovirus 3'-Utr y-Stem by restoring watson-Crick base pairs.
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Authors
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J.Zoll,
M.Tessari,
F.J.Van kuppeveld,
W.J.Melchers,
H.A.Heus.
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Ref.
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Rna, 2007,
13,
781-792.
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PubMed id
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Abstract
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The previously described NMR structure of a 5'-CU-3'/5'-UU-3' motif, which is
highly conserved within the 3'-UTR Y-stem of poliovirus-like enteroviruses,
revealed striking regularities of the local helix geometry, thus retaining the
pseudo-twofold symmetry of the RNA helix. A mutant virus with both pyrimidine
base pairs changed into Watson-Crick replicated as wild type, indicating the
functional importance of this symmetry relation in viral RNA replication. Here
we investigated the effect of changing only one of the two pyrimidine base pairs
to Watson-Crick. We determined the NMR structures of two Y-stem variants: one
containing the 5'-CU-3'/5'-AU-3' motif, which has been found in wild-type virus
isolates as well, and the other containing a 5'-CU-3'/5'-UG-3' motif, which is
not present in any enterovirus sequenced to date. Both structures show single
pyrimidine mismatches with intercalated bases. In the 5'-CU-3'/5'-AU-3' motif a
C-U Watson-Crick-type base pair is formed that retains the pseudo-twofold
symmetry, while in the 5'-CU-3'/5'-UG-3' motif a single asymmetric U-U mismatch
breaks the twofold symmetry. Surprisingly, for the nonnatural variant no effect
of the single base-pair replacement was observed on polioviral RNA replication
using an in vitro replicon assay.
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Headers
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