Liquid-chromatography-coupled SAXS for accurate sizing of aggregating proteins

Small-angle X-ray scattering and size-exclusion chromatography have been combined within a uni®ed experimental set-up to obtain molecular size information. Besides providing simultaneous corro-borative data bearing on the same question from two distinct experimental techniques, passing the samples over a gel ®ltration column immediately prior to illumination by X-rays provides both a more homogeneous sample and a continuous set of data as the concentration is extrapolated to zero. This greatly facilitates analysis of data from oligomerizing or aggregating proteins and increases the reliability of the results