title: NMR structure of the let-7 miRNA interacting with the site LCS1 of lin-41 mRNA from Caenorhabditis elegans.
abstract: We have determined the 3D structure of a 34-nt RNA construct, herein named LCS1co, which mimics the interaction of let-7 microRNA (miRNA) to one of its complementary binding sites, LCS1, in the 3'-untranslated region of lin-41 mRNA by solution-state NMR spectroscopy. let-7 miRNAs control the timing of development of the nematode Caenorhabditis elegans and are highly conserved in mammals. The sequence and structure of the two conserved let-7 complementary sites, LCS1 and LCS2, in the 3'-untranslated region of lin-41 mRNA are important for a proper downregulation of lin-41. The high-resolution NMR structure reveals details of the binding of let-7 miRNA to lin-41 mRNA which involves formation of a complex with non-canonical structural elements within the seed region. LCS1co exhibits a stem-loop structure with two stems, an asymmetric internal loop and an adenine bulge. Comparison with the NMR solution-state structure of the let-7:lin-41 complex involving the LCS2-binding site shows that conformational freedom of the asymmetric internal loop of LCS1co correlates with a smaller bend between the upper and lower stems in comparison to the well-defined asymmetric loop of LCS2co.
authors.affiliation: Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, Slovenia.
authors.forename: Mirko
authors.initials: M
authors.lastname: Cevec
authors.forename: Christophe
authors.initials: C
authors.lastname: Thibaudeau
authors.forename: Janez
authors.initials: J
authors.lastname: Plavec
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D020029:Base Pairing; D001665:Binding Sites; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D035683:MicroRNAs / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D029742:Caenorhabditis elegans Proteins; C410586:LIN-41 protein, C elegans; D035683:MicroRNAs; D014157:Transcription Factors; C474488:let-7 microRNA, C elegans