1u04: Difference between revisions

[[Image:1u04.gif|left|200px]]<br /><applet load="1u04" size="350" color="white" frame="true" align="right" spinBox="true"  

Argonaute proteins and small interfering RNAs (siRNAs) are the known signature components of the RNA interference effector complex RNA-induced silencing complex (RISC). However, the identity of "Slicer," the enzyme that cleaves the messenger RNA (mRNA) as directed by the siRNA, has not been resolved. Here, we report the crystal structure of the Argonaute protein from Pyrococcus furiosus at 2.25 angstrom resolution. The structure reveals a crescent-shaped base made up of the amino-terminal, middle, and PIWI domains. The Piwi Argonaute Zwille (PAZ) domain is held above the base by a "stalk"-like region. The PIWI domain (named for the protein piwi) is similar to ribonuclease H, with a conserved active site aspartate-aspartate-glutamate motif, strongly implicating Argonaute as "Slicer." The architecture of the molecule and the placement of the PAZ and PIWI domains define a groove for substrate binding and suggest a mechanism for siRNA-guided mRNA cleavage.

1U04 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pyrococcus_furiosus_dsm_3638 Pyrococcus furiosus dsm 3638]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1U04 OCA].  

[[Category: Hannon, G J.]]

[[Category: Smith, S K.]]

[[Category: Song, J J.]]

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