Comparison of the NMR spectroscopy solution structures of pyranosyl-rNA and its nucleo-delta-peptide analogue.

The design of polymers that could mimic biomolecules in their ability to form assemblies similar to ribo- and deoxyribonucleic acids has become an attractive field of chemical research, and NMR spectroscopy has played a vital role in the determination of the three-dimensional structure of these newly designed nonnatural polymers. The structure of a self-complementary octamer duplex of pyranosyl-RNA (pRNA) has been determined by using NMR spectroscopy experimental data and an Xplor structure calculation protocol. The structure has been compared with the structure of a duplex formed by a designed nucleo-delta-peptide analogue of pRNA. The two duplexes assume one predominant conformation and show a high structural similarity. The conformation type of both structures agrees with those predicted based on qualitative conformational analysis and both structures show a good convergence toward the average torsion angles derived by NMR spectroscopy.