Before revision:  On 15 crystallographic datasetsfor ribozymes, riboswitches, and other RNA domains, ERRASER/PHENIX corrects the majority of identifiable sugar pucker errors, steric clashes , suspicious backbone rotamers, and incorrect bond lengths/angles, while, on average, improving Rfree correlation to set-aside diffraction data by 0.010. As further confirmation of improved accuracy, the refinement enhances agreement between crystals solved by independent groups and between domains related by non-crystallographic symmetry (NCS). Finally, we demonstrate successful application of ERRASER on coordinates for an entire 30S ribosomal subunit. By rapidly and systematically disambiguating RNA model fitting, ERRASER enables RNA crystallography with significantly fewer errors .
After revision:  On 15 crystallographic datasetsfor ribozymes, riboswitches, and other RNA domains, ERRASER/PHENIX corrects the majority of steric clashes and anomalous backbone and bond geometries, as assessed by MolProbity. Furthermore, the method improves the average Rfree by 0.014, resolves functionally important discrepancies in protein-binding kink turns and group I ribozyme active sites, and refines low-resolution structures to better match higher resolution structures. By enabling such 'super-resolution' interpretation of crystallographic data, ERRASER is a unique application of RNA structure prediction that promises routine use in experimental structural biology .