Determination of multicomponent protein structures in solution using global orientation and shape restraints

A methodology that simultaneously utilizes residual dipolar couplings (RDC) and the small-angle X-ray scattering (SAXS) restraints to mutually orient subunits and define the global shape of multicomponent proteins and protein complexes is described. The method exhibited better solution structures for the proteins or protein complexes compared those obtained by either NMR or x-ray crystallography alone based on the pair-distance distribution functions (PDDF) calculated from experimental SAXS data and back-calculated from the structures.