Automated SAXS Measurements of Protein Solutions with a Laboratory Based SAXS System

Consecutive SAXS measurements of a lysozyme solution (13 mg/ml) in Na-Phosphate buffer (10 mM, pH=7.4) with an exposure time of 3 minutes each were carried out. The measured SAXS-spectra were accumulated successively, background-subtracted and fourier-transformed into real-space (using the program GNOM [1,2]) in order to obtain the distance distribution function p(r). After approximately 12 min exposure time a stable p (r) function with a radius of gyration of 16 Å for the protein could be obtained. This SAXS-curve can now be used for low-resolution shape simulations using the program DAMMIN [1,2].