Crystallization and data collection
ATP and MgCl2 were added to final concentrations of 0.8 mM and 1.8 mM, respectively, in the protein sample prior to crystallization by sitting-drop vapor-diffusion at 4°C (Text S1). Diffraction data were collected at the National Synchrotron Light Source beamline X29A on an ADSC Q315 detector through the Macromolecular Crystallography Research Resource (PXRR) mail-in crystallography program. Data processing and scaling was performed with the HKL2000 suite.