Structure of a Conserved Retroviral RNA Packaging Element by NMR Spectroscopy and Cry

[nmrlearner]

Structure of a Conserved Retroviral RNA Packaging Element by NMR Spectroscopy and Cryo-Electron Tomography.

Related Articles Structure of a Conserved Retroviral RNA Packaging Element by NMR Spectroscopy and Cryo-Electron Tomography.

J Mol Biol. 2010 Oct 6;

Authors: Miyazaki Y, Irobalieva RN, Tolbert B, Smalls-Mantey A, Iyalla K, Loeliger K, D'Souza V, Khant H, Schmid MF, Garcia E, Telesnitsky A, Chiu W, Summers MF

The 5'-untranslated regions (5'-UTRs) of all gammaretroviruses contain a conserved "double hairpin motif" (?(CD)) that is required for genome packaging. Both hairpins (SL-C and SL-D) contain GACG tetraloops that, in isolated RNAs, are capable of forming "kissing" interactions stabilized by two intermolecular G-C base pairs. We have determined the three-dimensional structure of the double hairpin from the Moloney Murine Leukemia Virus (MoMuLV) ([?(CD)](2), 132-nucleotides, 42.8 kDaltons) using a (2)H-edited NMR spectroscopy-based approach. This approach enabled the detection of (1)H-(1)H dipolar interactions that were not observed in previous studies of isolated SL-C and SL-D hairpin RNAs using traditional (1)H-(1)H correlated and (1)H-(13)C-edited NMR methods. The hairpins participate in intermolecular cross-kissing interactions (SL-C to SL-D' and SLC' to SL-D), and stack in an end-to-end manner (SL-C to SL-D and SL-C' to SL-D') that gives rise to an elongated overall shape (ca. 95 Å by 45 Å by 25 Å). The global structure was confirmed by cryo-electron tomography (cryo-ET), making [?(CD)](2) simultaneously the smallest RNA to be structurally characterized to date by cryo-ET and among the largest to be determined by NMR. Our findings suggest that, in addition to promoting dimerization, [?(CD)](2) functions as a scaffold that helps initiate virus assembly by exposing a cluster of conserved UCUG elements for binding to the cognate nucleocapsid domains of assembling viral Gag proteins.

PMID: 20933521 [PubMed - as supplied by publisher]



Source: PubMed