Extended Data Fig. 2: Comparison of HK68 virus and VLP M1 structures, and resolution measurements.
From: The native structure of the assembled matrix protein 1 of influenza A virus
a, Representative orthoslice through a HK68 virus tomogram. Scale bar, 50 nm. Morphology is representative of three independent preparations of virus. b, Projection through 1.8 nm of the M1 subtomogram average obtained from HK68 virus data. c, Global FSC curve for the structure of M1 from HK68 virus (black), and analysis of anisotropy by FSC curves in x, y and z directions (blue, green and red, respectively). d–f, As in a–c, for VLP data. Morphology is representative of five independent preparations of VLPs. g, The structure of M1 from HK68 virus derived from subtomogram averaging, shown as a pink isosurface and fitted with the M1 NTD crystal structure. Cylinders represent the secondary structure elements of the M1 CTD. h, As in g, but for the subtomogram averaging structure of M1 from VLPs. We did not observe density that might correspond to the cytoplasmic tail of HA. i, FSC calculated between the virus M1 and VLP M1 structures, indicating that the structures are the same up to a resolution of 9 Å.
