Fig. 5: Structure of the RSV Tâ=â1 icosahedron pentamer.

a Filtered cryo-EM micrograph of Tâ=â1 icosahedrons. The image is representative of the 2394 micrograph dataset. b Isosurface representation of the CA Tâ=â1 icosahedron determined by single-particle cryo-EM. One pentamer is highlighted in colors: cyanâCANTD; orangeâCACTD. c Isosurface representations of one Tâ=â1 pentamer from the structure shown in b. The density in the center of the petamer, coordinated by K17 and R21, may correspond to phosphate ions, which are the main negatively charged component of the assembly buffer. d Model of the RSV CA pentamer refined from the structure shown in b. e Comparison of the real-space refined model of the CA pentamer from Tâ=â1 particles and rigid-body fitted model of CA pentamer from polyhedrons. The low RMSD value of their backbone atoms shows that the two models are almost identical.