Movies were collected using a 300-kV Titan Krios G3i microscope (Thermo Fisher Scientific, USA) equipped with a K3 BioQuantum direct electron detector (Gatan, USA). Cryo-EM micrographs were automatically recorded via FEI EPU software (Thermo Fisher Scientific, USA) with the energy filter slit set to 20 eV (49 (link)). Each micrograph was collected at a total dose of 50 e−/Å2 fractionated into 40 frames, and the defocus was set in the range from −1.0 to −1.8 μm. A super-resolution mode was used at a nominal magnification of ×64,000 with a pixel size of 0.67 Å.
Before image processing, raw frames were aligned and summed with dose weighting under MotionCor2.1 with the final pixel size of 1.34 Å (50 (link)), and the Contrast Transfer Function parameters were determined by CTFFIND-4 (51 (link)). Image processing was mainly performed in RELION 3.1 (52 (link)) and cryoSPARC 3.1.0 (53 (link)).
Before image processing, raw frames were aligned and summed with dose weighting under MotionCor2.1 with the final pixel size of 1.34 Å (50 (link)), and the Contrast Transfer Function parameters were determined by CTFFIND-4 (51 (link)). Image processing was mainly performed in RELION 3.1 (52 (link)) and cryoSPARC 3.1.0 (53 (link)).
