The application of hybrid pixel detectors for in-house SAXS instrumentation with a view to combined chromatographic operation

This study analyses the potential for laboratory-based size-exclusion chromatography (SEC) integrated small-angle X-ray scattering (SAXS) instrumentation to characterize protein complexes. Using a high-brilliance home source in conjunction with a hybrid pixel X-ray detector, the efficacy of SAXS data collection at pertinent protein concentrations and exposure times has been assessed. Scattering data from SOD1 and from the complex of SOD1 with its copper chaperone, using 10 min exposures, provided data quality in the range 0.03 < q < 0.25 Å^-1 that was sufficient to accurately assign radius of gyration, maximum dimension and molecular mass. These data demonstrate that a home source with integrated SEC-SAXS technology is feasible and would enable structural biologists studying systems containing transient protein complexes, or proteins prone to aggregation, to make advanced preparations in-house for more effective use of limited synchrotron beam time.