Structural basis for 5 '-end-specific recognition of guide RNA by the A-fulgidus Piwi protein

Article

关键词: CRYSTAL-STRUCTURE;    ARGONAUTE2;    MICRORNA;    BINDING;    INTERFERENCE;    MECHANISMS;    CLEAVAGE;   

DOI  :  10.1038/nature03514

来源: SCIE

【 摘 要 】

RNA interference (RNAi) is a conserved sequence-specific gene regulatory mechanism(1-3) mediated by the RNA-induced silencing complex ( RISC), which is composed of a single-stranded guide RNA and an Argonaute protein. The PIWI domain, a highly conserved motif within Argonaute, has been shown to adopt an RNase H fold(4,5) critical for the endonuclease cleavage activity of RISC4-6. Here we report the crystal structure of Archaeoglobus fulgidus Piwi protein bound to double-stranded RNA, thereby identifying the binding pocket for guide-strand 5 '-end recognition and providing insight into guide-strand-mediated messenger RNA target recognition. The phosphorylated 5 ' end of the guide RNA is anchored within a highly conserved basic pocket, supplemented by the carboxy-terminal carboxylate and a bound divalent cation. The first nucleotide from the 5 ' end of the guide RNA is unpaired and stacks over a conserved tyrosine residue, whereas successive nucleotides form a four-base-pair RNA duplex. Mutation of the corresponding amino acids that contact the 5 ' phosphate in human Ago2 resulted in attenuated mRNA cleavage activity. Our structure of the Piwi-RNA complex, and that determined elsewhere(7), provide direct support for the 5 ' region of the guide RNA serving as a nucleation site for pairing with target mRNA and for a fixed distance separating the RISC-mediated mRNA cleavage site from the anchored 5 ' end of the guide RNA.

【 授权许可】

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