E

Macromolecules in Solution

“…The resulting 3 nm resolution model represents the volumes occupied by the rRNA and protein moieties in the entire ribosome [165]. The predicted protein-rRNA map is in remarkably good agreement with the later high-resolution crystallographic models of the ribosomal subunits from other species [88,140,166]. It is interesting that the map obtained from solution scattering reveals peripheral proteins in the large ribosomal subunit (so-called L1 and L7/L12), which cannot be seen in the crystal structure of the 50S subunit from Haloarcula marismortui [140], apparently because of their flexibility, but they are revealed in the crystallographic model of the complete 70S ribosome from T. thermophilus [167].…”

“…The classical example illustrating the power of selective deuteration is that of the selective labelling of protein pairs in the 30S ribosomal subunit Escherichia coli which led to a complete three-dimensional map of the positions of ribosomal proteins by triangulation [87]. Comparison of this map, which predicted the centres of mass of 21 proteins with the high-resolution structure of the small ribosomal subunit from Thermus thermophilus determined 15 years later [88] indicated that the positions of only five smaller proteins were significantly different from those in the crystallographic model. The discrepancy can be attributed to poor signal-to-noise ratio of the scattering data from small labels and possibly also to imperfection of the reconstitution procedure employed for the labelling.…”