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Solution conformation of an RNA hairpin loop
J D Puglisi1, J R Wyatt, I Tinoco
1Department of Chemistry, University of California, Berkeley 94720.
Biochemistry
|May 11, 1990
Summary
This study used NMR spectroscopy to analyze an RNA hairpin, revealing a stable A-form duplex with an unusual A+.C base pair. This protonated base pair slightly reduces the hairpin
Area of Science:
- Molecular Biology
- Biophysics
- Structural Biology
Background:
- RNA hairpins are crucial for gene regulation and cellular processes.
- Understanding RNA structure, including unusual base pairing, is key to deciphering function.
Purpose of the Study:
- To elucidate the three-dimensional structure and stability of a specific RNA hairpin.
- To investigate the role of an unusual adenine-cytosine (A.C) base pair in RNA hairpin stability.
Main Methods:
- One- and two-dimensional Nuclear Magnetic Resonance (NMR) spectroscopy.
- Analysis of exchangeable and nonexchangeable proton spectra.
- Absorbance melting curves for stability assessment.
Main Results:
- The RNA sequence forms a stable six base-pair stem and a three-nucleotide loop in an A-conformation.
- An unusual protonated adenine-cytosine (A+.C) base pair was identified at the junction of the stem and loop.
- The A+.C base pair was found to be approximately 2 kcal/mol less stable than a standard A.U pair.
Conclusions:
- The RNA hairpin adopts a well-defined A-form structure stabilized by base stacking and an A+.C base pair.
- Protonation of adenine in the A+.C base pair influences the overall stability of the RNA hairpin.