2bgg: Difference between revisions

RNA interference and related RNA silencing phenomena use short antisense, guide RNA molecules to repress the expression of target genes. Argonaute, proteins, containing amino-terminal PAZ (for PIWI/Argonaute/Zwille), domains and carboxy-terminal PIWI domains, are core components of these, mechanisms. Here we show the crystal structure of a Piwi protein from, Archaeoglobus fulgidus (AfPiwi) in complex with a small interfering RNA, (siRNA)-like duplex, which mimics the 5' end of a guide RNA strand bound, to an overhanging target messenger RNA. The structure contains a highly, conserved metal-binding site that anchors the 5' nucleotide of the guide, RNA. The first base pair of the duplex is unwound, separating the 5', nucleotide of the guide from the complementary nucleotide on the target, strand, which exits with the 3' overhang through a short channel. The, remaining base-paired nucleotides assume an A-form helix, accommodated, within a channel in the PIWI domain, which can be extended to place the, scissile phosphate of the target strand adjacent to the putative slicer, catalytic site. This study provides insights into mechanisms of target, mRNA recognition and cleavage by an Argonaute-siRNA guide complex.

2BGG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Archaeoglobus_fulgidus Archaeoglobus fulgidus] with MN as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BGG OCA].  

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