The ‘converted’ NMR Restraints Grid NRG data and the chemical shifts from BMRB were validated by CING to create: NRG-CING (‘energy king’). This process is published here. The WHY-NOT database can tell you why a certain entry is absent from NRG-CING. Enjoy and please report our little critters.
WHY_NOT lists why your favorite entry might not (yet) be in a database like NRG-CING.