Extended Data Fig. 1: Cryo-EM analyses of FluPolH5N1 bound to vRNA promoter.

a. A representative cryo-EM micrograph of FluPol_H5N1 bound to vRNA promoter. b, c. Representative 2D classifications of FluPol_H5N1 complex particles. White arrows indicate the vRNA promoter and yellow arrows indicate the flexible domains above the core region. d. Euler angle distributions of FluPol_H5N1 complex in the final 3D reconstructions. e. Local resolution evaluations of cryo-EM maps of FluPol_H5N1 complex by ResMap. f, g. Gold standard Fourier shell correlation curves for resolution evaluation of core region (f) and full-length (g) at 0.143 FSC. The FSC curves of the final refined models versus cryo-EM maps at 0.5 FSC are also shown. h. Representative regions of the cryo-EM structure of FluPol_H5N1 are shown as cartoon representation colored as same as those in Fig. 1a. The density maps of motif pre-A (residues 225-243) and motif C (residues 436-453) were shown. i. The density maps of 3′-vRNA and 5′-vRNA. J, k. Plots of the global half-map FSC (solid red line) and map-to-model FSC (dotted green line) of full-length (j) and core region (k) FluPolH5N1 and together with the spread of directional resolution values defined by ±1σ from the mean.