Synchrotron SAXS
data from solutions of
HOTag6 tetramerization domain followed by a Gly-Ser linker fused to human monoubiquitin
in
20 mM sodium phosphate, 0.5 mM EDTA, 0.02 % NaN3, pH 6.8
were collected
on the
BioCAT 18ID beam line
at the Advanced Photon Source (APS), Argonne National Laboratory storage ring
(Lemont, IL, USA)
using a Pilatus3 X 1M 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) SAS was employed. The SEC parameters were as follows: A 300.00 μl sample
at 4.7 mg/ml was injected at a 0.60 ml/min flow rate
onto a GE Superdex 200 Increase 10/300 column
at 20°C.
37 successive
0.500 second frames were collected.
The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.
HOTag6 is a ~30-amino-acid tetramerization domain followed by a Gly-Ser linker followed by the sequence for human monoubiquitin (UniProt ID: P0CG47, https://www.uniprot.org/uniprot/P0CG47, amino acids 1-76) . This is a designed protein (no natural variant exists). The HOTag6 sequence is from the Shu group at the University of California, San Francisco (https://doi.org/10.1016/j.molcel.2017.12.008).