Variable Macro X Domain of SARS-CoV-2 Retains the Ability to Bind ADP-ribose

David N. Frick; Rajdeep S. Virdi; Nemanja Vuksanovic; Narayan Dahal; Nicholas R Silvaggi

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.31.014639 doi: bioRxiv preprint MRC UV-transmissible sitting drop plate. Large, diffraction-quality crystals grew directly from a number of the screen conditions. The crystal ultimately used for structure determination grew from condition D9: 0.12 M alcohols [0.02 M each 1,6-hexanediol, 1-butanol, 1,2-propanediol, 2-propanol, 1,4-butanediol, and 1,3-propanediol], 0.1 M buffer system 3, pH 8.5 [0.05 M each TRIS and bicine], and 30% precipitant mix 1 [20% poly(ethylene glycol) (PEG) 500 monomethylether, 10% PEG 20,000]. Large, thick plates grew within 1 week at 22 °C. Owing to the high concentration of PEG 500 MME, the crystal did not require additional cryo-protection and was flash-cooled by looping it directly from the sitting drop and plunging it into liquid nitrogen.