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PDBsum entry 5guh
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Hydrolase/RNA
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PDB id
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5guh
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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 silkworm piwi-Clade argonaute siwi bound to pirna.
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Authors
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N.Matsumoto,
H.Nishimasu,
K.Sakakibara,
K.M.Nishida,
T.Hirano,
R.Ishitani,
H.Siomi,
M.C.Siomi,
O.Nureki.
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Ref.
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Cell, 2016,
167,
484.
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PubMed id
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Abstract
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PIWI-clade Argonaute proteins associate with PIWI-interacting RNAs (piRNAs) and
silence transposable elements in animal gonads. Here, we report the crystal
structure of a silkworm PIWI-clade Argonaute, Siwi, bound to the endogenous
piRNA, at 2.4 Å resolution. Siwi adopts a bilobed architecture consisting of
N-PAZ and MID-PIWI lobes, in which the 5' and 3' ends of the bound piRNA are
anchored by the MID-PIWI and PAZ domains, respectively. A structural comparison
of Siwi with AGO-clade Argonautes reveals notable differences in their
nucleic-acid-binding channels, likely reflecting the distinct lengths of their
guide RNAs and their mechanistic differences in guide RNA loading and cleavage
product release. In addition, the structure reveals that Siwi and prokaryotic,
but not eukaryotic, AGO-clade Argonautes share unexpected similarities, such as
metal-dependent 5'-phosphate recognition and a potential structural transition
during the catalytic-tetrad formation. Overall, this study provides a critical
starting point toward a mechanistic understanding of piRNA-mediated transposon
silencing.
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