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SAXS data for non-structural protein 9 (Nsp9) from SARS-CoV-2 with the synthetic 14-nucleotide tetraloop RNA fragment from E. coli 4.5S (4.5Stet) at 1:1 molar ratio in 25 mM sodium phosphate pH 6.0, 150 mM NaCl, 1 mM DTT with 5% glycerol as a stabilizer. Data were collected at the BioSAXS beamline of the Australian Synchrotron. The X-ray wavelength was 1.002 Å; the detector was a Dectris Pilatus3X-2M with in-vacuum movable detector system, 172 µm2 pixel size, 25 Hz frame rate, count rate per detector pixel was 39.95 counts/s; the sample-to-detector distance was 3150 mm to yield a measured q-range 0.0051–0.4768 Å-1; exposures were 1 second for 16 exposures and absolute scaling used water as a secondary standard. Samples were spun at 21,000 x g for 5 min and degassed in a vacuum chamber for 5 min just prior to loading onto a 96-well plate for measurement. Concentration values are for the nominal Nsp9 component prior to that procedure according to absorbance at 280 nm. Shown here are the Nsp9:4.5Stet data with 6 mg/mL Nsp9, where the protein alone would be fully dimeric. The small oscillations in the low-q residual difference plots and tails on the DAMMIN envelops are consistent with a dimeric Nsp9 with a weakly bound 4.5Stet with a population of free 4.5Stet present. A full concentration series (nominal Nsp9 concentration 0.025–6 mg/mL) was performed and data for all concentrations are available in zipped folders with this deposition.
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s, nm-1
