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Dipolar coupling interactions represent an extremely valuable source of long-range distance and angle information that was previously not available for solution structure determinations of macromolecules. This is because observation of these dipolar coupling data requires creating an anisotropic environment for the macromolecule. Here we introduce a new(More)
The most frequently occurring RNA hairpins in 16S and 23S ribosomal RNA contain a tetranucleotide loop that has a GNRA consensus sequence. The solution structures of the GCAA and GAAA hairpins have been determined by nuclear magnetic resonance spectroscopy. Both loops contain an unusual G-A base pair between the first and last residue in the loop, a(More)
Species of RNA that bind with high affinity and specificity to the bronchodilator theophylline were identified by selection from an oligonucleotide library. One RNA molecule binds to theophylline with a dissociation constant Kd of 0.1 microM. This binding affinity is 10,000-fold greater than the RNA molecule's affinity for caffeine, which differs from(More)
The vicinal amide proton-C alpha proton spin-spin coupling constants, JHN alpha, in the globular protein basic pancreatic trypsin inhibitor (BPTI) have been measured using phase-sensitive correlated spectroscopy at high digital resolution. In conjunction with the crystal structure of BPTI, these data were used to calibrate the correlation between 3JHN alpha(More)
The iron responsive element (IRE) is a approximately 30 nucleotide RNA hairpin that is located in the 5' untranslated region of all ferritin mRNAs and in the 3' untranslated region of all transferrin receptor mRNAs. The IREs are bound by two related IRE-binding proteins (IRPs) which help control intracellular levels of iron by regulating the expression of(More)
To visualize the interplay of RNA structural interactions in a ligand binding site, we have determined the solution structure of a high affinity RNA-theophylline complex using NMR spectroscopy. The structure provides insight into the ability of this in vitro selected RNA to discriminate theophylline from the structurally similar molecule caffeine. Numerous(More)
RNA hairpin loops containing a GNRA consensus sequence are the most frequently occurring hairpins in a variety of prokaryotic and eukaryotic RNAs. These tetraloops play important functional roles in RNA folding, in RNA-RNA tertiary interactions and as protein binding sites. Homo and heteronuclear NMR spectroscopy have been used to determine the structures(More)
The hammerhead ribozyme is a small RNA motif that catalyzes the cleavage and ligation of RNA. The well-studied minimal hammerhead motif is inactive under physiological conditions and requires high Mg(2+) concentrations for efficient cleavage. In contrast, natural hammerheads are active under physiological conditions and contain motifs outside the catalytic(More)
The U-turn (uridine turn) is an RNA structural motif that contains a change in backbone direction stabilized by specific interactions across the bend. It was first identified in the anticodon loop and the T-loop of yeast tRNA(Phe) (Quigley & Rich, 1976, Science 194:796-806) and has recently also been found in the crystal structure of the hammerhead ribozyme(More)
An RNA aptamer containing a 15-nt binding site shows high affinity and specificity for the bronchodilator theophylline. A variety of base modifications or 2' deoxyribose substitutions in binding-site residues were tested for theophyllinebinding affinity and the results were compared with the previously determined three-dimensional structure of the(More)