Classification of RNA backbone conformation into rotamers using 13C' chemical shifts: How far we can go?

The conformational space of the ribose-phosphate backbone is very complex as is defined in terms of six torsional angles. To help delimit the RNA backbone conformational preferences 46 rotamers have been defined in terms of the these torsional angles. In the present work, we use the ribose experimental and theoretical 13C9; chemical shifts data and machine learning methods to classify RNA backbone conformations into rotamers and families of rotamers. We show to what extent the use of experimental 13C9; chemical shifts can be used to identify rotamers and discuss some problem with the theoretical computations of 13C9; chemical shifts.