Structural hierarchy of several proteins observed by wide-angle solution scattering

In the present study using a high-intensity X-ray beam from a third-generation synchrotron radiation source, it is demonstrated that a wide-angle X-ray scattering (WAXS) profile from several globular proteins in solution can reflect not only the overall structures (similar to 300 Angstrom distance resolution) but also intramolecular structures ranging to secondary structures (similar to2.5 Angstrom distance resolution). The proteins treated in the present experiments are classified as different types of structure categories, namely, as all-alpha, all-beta and alpha + beta proteins. Here the full-range experimental scattering curves are compared with the theoretical curves, suggesting a further availability of the SR-WAXS method for studies of structure hierarchy and the function of proteins in solutions.