Fig. 3: Atomically ordered structure of GOLLD homo-14-mer.
From: Naturally ornate RNA-only complexes revealed by cryo-EM
a, Representative micrograph (23,281 micrographs total) and 2D class averages. Scale bar, 50 nm. b, The 3.0 Å cryo-EM reconstruction of GOLLD with D7 symmetry, coloured by chain. In the top view (left), the inner circle is labelled. c, The 5′ (blue, residues 1–420) and 3′ (red, residues 421–833) regions of GOLLD organize into the cap and a ring of the half-shell of the nanocage, respectively. To demonstrate the separation of domains, the four regions are artificially moved apart. d, The secondary structure of GOLLD. Only one chain is displayed in full, nucleotides participating in intermolecular interactions that are from other chains are circled in light or dark grey. e, One chain of GOLLD is depicted in rainbow, intermolecular interactions or bridges are labelled, with kissing loops labelled in magenta, A-minor interactions in cyan and other interactions in lime. The same interaction, but between different pairs of chains, share the same number. Each chain interacts with four other chains. f, Same as e, but rotated and is cut away to show the rainbow-labelled chain from the interior of the nanocage with the disordered linker labelled in pink (nucleotides 497–538). g–j, Select intramolecular interactions. k–t, Intermolecular interactions as labelled in e. The sharpened cryo-EM map is displayed at the following contours: 12σ (e,f,i), 14σ (c,o), 16σ (b,n), 18σ (s,q), 20σ (k–m,p), 22σ (t), 25σ (h,i) and 30σ (g,j).
