Fig. 10.

An example showing the importance of local CTF refinement. (a) The raw micrograph of dynactin (Dataset-6). (b) The local defocus for this particle determined by Gctf is 3.92 μm. The red arrow indicates the fitting is almost perfect up to 5 Å. The black curve represents the circularly averaged LAS of particle 1; the blue curve represents the comparison with Gctf determination. (c) Similar to (b) but for particle 2. The defocus of this particle is 3.87 μm. The fitting of CTF is also perfect up to 5 Å. (d) Comparison between the circularly averaged LAS of particle 1 and simulated amplitude spectra using defocus of particle 2. In contrast to (b) or (c), the simulated CTF curve does not fit the observed curve at high resolution, indicating the importance the local refinement for near atomic resolution reconstruction.