Extended Data Fig. 8: Putative MDF1 bound to the hibernating ribosome dimer of S. lophii.

a Close-up of the L1 stalk region and E-site of a multibody single particle map of the isolated 70S ribosome from S. lophii with the atomic model fitted (multicolour, liquorice representation). b shows the same region highlighting the map region corresponding to the tRNA in yellow. The tRNA density shows a clear T-shape. c, d In situ subtomogram average of the hibernating 100S ribosome of S. lophii (half-dimer map) with the atomic model fitted in c and the map region occupied by the putative MDF1 colored green in d. The density assigned to MDF1 fits the dimensions and shape of the molecule. The density also clearly lacks the tRNA acceptor arm seen in the single particle map of the isolated 70S ribosome (a, b). e Atomic model of the E. cuniculi 70S hibernating ribosome (7QEP¹⁸) fitted into the in situ map of the S. lophii hibernating 100S ribosome (half dimer map). f shows the map region overlapping with MDF1 in green. The model of E. cuniculi’s MDF1 fits the location, size and shape of the S. lophii density. g Map of the hibernating 70S ribosome from E. cuniculi (EMD-13936) with the corresponding atomic model of E. cuniculi (7QEP) fitted, and the map region corresponding to MDF1 coloured in green (h). The dimensions and shape of the map region assigned to MDF1 is almost identical to that within the hibernating 100S ribosome of S. lophii (c & d). All single particle maps have been filtered to a resolution comparable to that of the subtomogram average. The coloured map regions in b, d, f and h have been produced using the color zone command in ChimeraX.