| Nucleic acids are compounds of essential importance for all living organisms. Although the general structural features of regular DNAs and RNAs are well known, there exist a plethora of structural motifs different from the regular double helix. Detailed knowledge of the structural characteristics is necessary for understanding their biological function. NMR spectroscopy allows studying the structures of nucleic acids oligomers in solution at close to physiological conditions. The structures of d(C4G4) and d(G4C4) duplexes and d(GCGAAGC) hairpin were among those solved in our laboratory. In order to delineate the relationships between the structures, thermodynamic stabilities and biological function of nucleic acids it is highly desirable to complement the structural studies by characterization of equilibrium conformational fluctuations. Measurement of nuclear spin relaxation by NMR spectroscopy is a powerful approach for studying intramolecular motions at atomic resolution on the nanosecond to picosecond time scale. We have studied the dynamics of two RNA hairpins containing UUCG and GCAA tetraloops by 15N and 13C relaxation. |
