Modeling of protein solution structures

Reconstructions of low-resolution three-dimensional solution structures of proteins from one-dimensional small-angle X-ray scattering (SAXS) data can be achieved by trial-and-error or ab initio approaches. It is demonstrated that all tested advanced approaches (GA, DAMMIN, SAXS3D) reproduce the shape of three selected test proteins (malate synthase, cellobiose dehydrogenase, extracellular hemoglobin). The agreement between SAXS profiles and functions derived from beaded model structures and experimental data, however, varies with respect to the angular range covered; the same holds true for the accuracy of the molecular parameters calculated from the respective patterns. The uniqueness of the structures obtained is crucial and may be increased by combined use of different approaches. The obtained models can be used for predicting both structural and hydrodynamic data with a high degree of probability.