4f1n

Publication Abstract from PubMed

The RNA-induced silencing complex, comprising Argonaute and guide RNA, mediates RNA interference. Here we report the 3.2 A crystal structure of Kluyveromyces polysporus Argonaute (KpAGO) fortuitously complexed with guide RNA originating from small-RNA duplexes autonomously loaded by recombinant KpAGO. Despite their diverse sequences, guide-RNA nucleotides 1-8 are positioned similarly, with sequence-independent contacts to bases, phosphates and 2'-hydroxyl groups pre-organizing the backbone of nucleotides 2-8 in a near-A-form conformation. Compared with prokaryotic Argonautes, KpAGO has numerous surface-exposed insertion segments, with a cluster of conserved insertions repositioning the N domain to enable full propagation of guide-target pairing. Compared with Argonautes in inactive conformations, KpAGO has a hydrogen-bond network that stabilizes an expanded and repositioned loop, which inserts an invariant glutamate into the catalytic pocket. Mutation analyses and analogies to ribonuclease H indicate that insertion of this glutamate finger completes a universally conserved catalytic tetrad, thereby activating Argonaute for RNA cleavage.

Structure of yeast Argonaute with guide RNA.,Nakanishi K, Weinberg DE, Bartel DP, Patel DJ Nature. 2012 Jun 20;486(7403):368-74. doi: 10.1038/nature11211. PMID:22722195^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.