Random coil index
Random coil index (RCI) predicts protein flexibility by calculating an inverse weighted average of backbone secondary chemical shifts and predicting values of model-free order parameters as well as per-residue RMSD of NMR and molecular dynamics ensembles from this parameter. The key advantages of this protocol over existing methods of studying protein flexibility are it does not require prior knowledge of a protein's tertiary structure, it is not sensitive to the protein's overall tumbling and it does not require additional NMR measurements beyond the standard experiments for backbone assignments.