A pseudopotential for improving the packing of ellipsoidal protein structures determined from NMR data

A pseudopotential has been introduced into NMR protein structure determination that effectively restrains molecular volume based on the observation that rigid, well-packed protein structures are approximately ellipsoidal. Allowing an ellipsoidal shape is more general than the single approximately spherical shape imposed by the radius of gyration pseudopotential introduced previously. We demonstrate that this new gyration volume term improves structures both during the calculation of an initial unknown fold and during final refinement.