Fig. 4: Resolution improvement and validation using in vitro samples of HIV-1 Gag and apoferritin.

a, Resolution improvements obtained by nextPYP using 43 tilt series from EMPIAR-10164 after fully constrained refinement (4.2 Å), dose-weighted reconstruction (3.7 Å), region-based refinement (3.2 Å), particle-based CTF refinement (3.2 Å) and video frame refinement (3.0 Å). Corresponding Fourier shell correlation (FSC) curves calculated between half maps (0.143 cutoff criteria was used to determine resolution) (top). Alpha helical segment with model fit into map showing the progression in resolution with each step. b, High-resolution structure of apoferritin obtained using 31,890 particles extracted from 100 tilt series (EMPIAR-11273). FSC plots between half maps showing incremental improvements in resolution from each processing step (top). The 1.8 Å resolution reconstruction and selected high-resolution features with atomic model fit into the density (bottom).