The SARS-Unique Domain (SUD) of SARS Coronavirus Contains Two Macrodomains That Bind G-Quadruplexes

Tan, Jinzhi; Vonrhein, Clemens; Smart, Oliver S.; Bricogne, Gerard; Bollati, Michela; Kusov, Yuri; Hansen, Guido; Mesters, Jeroen R.; Schmidt, Christian L.; Hilgenfeld, Rolf

Many SUD core crystals had to be tested for diffraction until one yielding data to 2.2 Ã… resolution was found. The best diffracting crystals belonged to space group P2 1 . Under the same crystallization conditions, a second crystal form belonging to space group P1 was observed, diffracting to lower resolution of about 2.8 Ã… . Crystals were cryoprotected in reservoir solution that included 30% glycerol, and were harvested into a loop prior to flash-cooling in liquid nitrogen. All data were collected at 100 K from a single crystal each at beamline BL14.2, BESSY (Berlin, Germany), using an MX225 CCD detector (Rayonics), or at beamline I911-2 at MAX-lab (Lund, Sweden), using a Mar165 CCD detector (Marresearch). Data were processed with MOSFLM [59] , and reduced and scaled using the SCALA [60] program from the CCP4 suite [61] . Crystals belonging to space group P2 1 had unitcell parameters a = 46. 36