Article

Crystal structure and ligand binding of the MID domain of a eukaryotic Argonaute protein.

Department of Biochemistry, Max Planck Institute for Developmental Biology, Spemannstrasse 35, Tübingen D-72076, Germany.
EMBO Reports (Impact Factor: 7.19). 07/2010; 11(7):522-7. DOI: 10.1038/embor.2010.81
Source: PubMed

ABSTRACT Argonaute (AGO) proteins are core components of RNA-induced silencing complexes and have essential roles in RNA-mediated gene silencing. They are characterized by a bilobal architecture, consisting of one lobe containing the amino-terminal and PAZ domains and another containing the MID and PIWI domains. Except for the PAZ domain, structural information on eukaryotic AGO domains is not yet available. In this study, we report the crystal structure of the MID domain of the eukaryotic AGO protein QDE-2 from Neurospora crassa. This domain adopts a Rossmann-like fold and recognizes the 5'-terminal nucleotide of a guide RNA in a manner similar to its prokaryotic counterparts. The 5'-nucleotide-binding site shares common residues with a second, adjacent ligand-binding site, suggesting a mechanism for the cooperative binding of ligands to the MID domain of eukaryotic AGOs.

0 Bookmarks
 · 
87 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: RNA metabolism, including RNA synthesis and RNA degradation, is one of the most conserved biological systems and has been intensively studied; however, the degradation network of ribonucleases (RNases) and RNA substrates is not fully understood.
    BMC genomics. 05/2014; 15(1):386.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The active components of the RNAi are 21 nucleotides long dsRNAs containing a 2 nucleotide overhang at the 3' end, carrying 5'-phosphate and 3'-hydroxyl groups (siRNAs). Structural analysis revealed that the siRNA is functionally bound at both ends to RISC. Terminal modifications are considered with interest as the introduction of chemical moieties interferes with the 3' overhang recognition by the PAZ domain and the 5'-phosphate recognition by the MID and PIWI domains of RISC. Herein, we report the synthesis of modified siRNAs containing terminal amide linkages by introducing hydroxyethylglycine PNA (hegPNA) moieties at 5', and at 3' positions and on both terminals. Results of gene silencing studies highlight that some of these modifications are compatible with the RNAi machinery and markedly increase the resistance to serum-derived nucleases even after 24 h of incubation. Molecular docking simulations were attained to give at atomistic level a clearer picture of the effect of the most performing modifications on the interactions with the human Argonaute 2 PAZ, MID, and PIWI domains. This study adds another piece to the puzzle of the heterogeneous chemical modifications that can be attained to enhance the silencing efficiency of siRNAs.
    BioMed research international. 01/2014; 2014:901617.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: MicroRNAs (miRNAs) directly and indirectly impact tumorigenesis. To perform their myriad roles, not only must precise miRNAs be generated by miRNA machinery genes but these genes such as Drosha, DGCR8, Dicer1, XPO5, TRBP, and AGO2 also have specific expression patterns, protein binding partners, and biochemical capabilities in different cancers. The published studies have demonstrated that changeable expression levels of Drosha, DGCR8, Dicer, XPO5, AGO2 and TRBP were associated with several tumors such as breast, colorectal, gastric, lung, ovarian and prostate cancer and alterations in the miRNA machinery play important roles in the carcinogenesis of these tumors. Here, we review their biological structures and functions with an eye towards understanding they could serve as cancer biomarkers.
    Frontiers in Oncology 05/2014; 4:1-9.

Full-text (2 Sources)

Download
4 Downloads
Available from
Aug 21, 2014