a, Atomic structure of Nog2 (2–472 amino acids) with domains separately coloured, highlighting the N-terminal extension of Nog2. The orientation of Nog2 in the pre-60S particle is shown in the left thumbnail. b, Local resolution map of Nog2. Segmented Nog2 density map is coloured according to the scale bar below. c, Zoom-in view of the H69–H71 region in the map of state 1, superimposed with atomic models of Nog2, H69 and H71. d, Same as c, but for the density map of the mature 60S subunit. e, Comparison of H69–H71 in the two density maps.