a, The NTD of Nog1 inserts directly into the two strands of H89. GD, GTPase domain. b, Superimposition of the NTD of Nog1 with H89 in its mature conformation, displaying a steric clash in the terminal tip of the NTD of Nog1. c, Structural comparison of H89 in the pre-60S and mature conformations. d, The CTE of Nog1 interacts with multiple assembly factors (Tif6, Rlp24, Arx1) and r-proteins (L3, L31, L22, L19, L35) in an arc region of the pre-60S particle. The overview is shown in the left thumbnail. The position and direction of polypeptide tunnel exit is denoted by a black diamond. e, The last C-terminal portion of Nog1 goes into the polypeptide tunnel and interacts with L4, L17, and L39 (see also Extended Data Fig. 6).