Structure of a small RNA hairpin.
AUTOR(ES)
Davis, P W
RESUMO
The hairpin stem-loop form of the RNA oligonucleotide rCGC(UUU)GCG has been studied by NMR spectroscopy. In 10 mM phosphate buffer this RNA molecule forms a unimolecular hairpin with a stem of three base pairs and a loop of three uridines, as judged by both NMR and UV absorbance melting behavior. Distance and torsion angle restraints were determined using homonuclear proton-proton and heteronuclear proton-phosphorus 2-D NMR. These values were used in restrained molecular dynamics to determine the structure of the hairpin. The stem has characteristics of A-form geometry, although distortion from A-form occurs in the 3'-side of the stem, presumably to aid in accommodating the small loop. The loop nucleotides adopt C2'-endo conformations. NOE's strongly suggest stacking of the uracils with the stem, especially the first uracil on the 5'-side of the loop. The reversal of the chain direction in the loop seems to occur between U5 and U6. Loop structures produced by molecular dynamics simulations had a wide range of conformations and did not show stacking of the uracils. A flexible loop with significant dynamics is consistent with all the data.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=309150Documentos Relacionados
- Structure of a U.U pair within a conserved ribosomal RNA hairpin.
- Transcription termination at intrinsic terminators: the role of the RNA hairpin.
- The use of non-uniform deuterium labelling ['NMR-window'] to study the NMR structure of a 21mer RNA hairpin.
- Optimal Tat-mediated activation of the HIV-1 LTR promoter requires a full-length TAR RNA hairpin.
- NMR structure of a ribosomal RNA hairpin containing a conserved CUCAA pentaloop