Extended Data Fig. 3: Electron microscopy density of protein components.

a, e, f, i, k, l, Full densities of TERT (a), histone H2A (e), histone H2B (f), TCAB1 (i), 5′ H/ACA tetramer (k) and 3′ H/ACA tetramer (l). b, Close-up view of the active site density of TERT with an empty nucleotide-binding pocket (Extended Data Fig. 6f). c, d, Representative electron microscopy densities of TERT. g, h, j, Representative electron microscopy densities of histone H2A (g), histone H2B (h) and TCAB1 (j). m, Close-up view of the density of the N-terminal extension of the 5′ dyskerin bound to a hydrophobic pocket within the 3′ dyskerin (Fig. 4c). n, Close-up view of the density of helix 352–375 of the 3′ dyskerin bound to the equivalent hydrophobic pocket as in m within the 5′ dyskerin (Fig. 4d). o, Close-up view of the density of the P8 stem loop of hTR, which contains the CAB and BIO boxes that interact with TCAB1 and the 3′ NHP2 (Extended Data Figs. 4l, 8d). p, Close-up view of the density of the H and ACA boxes interacting with the two dyskerin molecules (Extended Data Figs. 4k, 8c).