Synchrotron SAXS data from solutions of MBP-tagged CpoS C-ter in 20 mM Tris-HCl pH 7.5, 50 mM NaCl, 1mM EDTA, 2% glycerol and 1 mM DTT were collected on the BioCAT 18-ID-D beamline at the Advanced Photon Source (APS), Argonne National Laboratory storage ring (Lemont, IL, USA) using a Eiger2 XE 9M detector at a sample-detector distance of ~3.7 m and at a wavelength of λ = 0.1033 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). In-line size-exclusion chromatography (SEC)-SAXS was employed. The SEC parameters were as follows: A 250 μl sample at 1 mg/ml was injected at a 0.60 ml/min flow rate onto a Superose 6 Increase GL 10/300 column (GE healthcare) at 22°C. 2500 successive frames (0.3 second exposure time per second period) were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; An average of 30 frames before and after the eluted peaks were used for buffer subtraction. Protein peaks were also ran through evolving factor analysis (EFA) to deconvolute into the individual scattering components.
s, nm-1
