title: Invisible RNA state dynamically couples distant motifs.
abstract: Using on- and off-resonance carbon and nitrogen R1ρ NMR relaxation dispersion in concert with mutagenesis and NMR chemical shift fingerprinting, we show that the transactivation response element RNA from the HIV-1 exists in dynamic equilibrium with a transient state that has a lifetime of ∼2 ms and population of ∼0.4%, which simultaneously remodels the structure of a bulge, stem, and apical loop. This is accomplished by a global change in strand register, in which bulge residues pair up with residues in the upper stem, causing a reshuffling of base pairs that propagates to the tip of apical loop, resulting in the creation of three noncanonical base pairs. Our results show that transient states can remodel distant RNA motifs and possibly give rise to mechanisms for rapid long-range communication in RNA that can be harnessed in processes such as cooperative folding and ribonucleoprotein assembly.
authors: Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055;
authors: Janghyun
authors: J
authors: Lee
authors: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290; and.
authors: Elizabeth A
authors: EA
authors: Dethoff
authors: Department of Biochemistry and Chemistry, Duke University School of Medicine, Durham, NC 27710 hashim.al.hashimi@duke.edu.
authors: Hashim M
authors: HM
authors: Al-Hashimi
mesh_terms: D020029:Base Pairing; D016325:HIV Long Terminal Repeat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000235:genetics*; D013816:Thermodynamics
chemical_list: D012367:RNA, Viral
keywords: NMR spectroscopy; R1ρ relaxation dispersion; dynamics; nucleic acids