Figure 7: The helix H84 in the 60S r-subunit, the symportin Syo1 and the p53 regulator MDM2 share the same binding site on L11 r-protein. (A) Structure of the 5S RNP as is assembled in the mature 60S r-subunit bound to 25S rRNA (nucleotides 2651-2750 comprising helices H83, H84, H85 and H86). (B) Interaction of a specific region of Syo1, called Syo1-HS (amino acids 328-384), with L11 in the context of the 5S RNP. (C) Structure of the 5S RNP bound to a distinct fragment of MDM2 (amino acids 293-334). The fragment of 25S rRNA is coloured in yellow, that of Syo1 in light gold, and that of MDM2 in dark gold; 5S rRNA in highlighted in red, L5 in cyan and L11 in blue. PDB ID: The 5S RNP bound to 25S rRNA was taken from 3U5I and 3U5H [44]; Syo1-HS fragment was extracted from 5AFF [163] after superimposing the structure shown here with that present in the PDB file 4GMN [144]; MDM2 fragment was taken from 4XXP [164] after superimposing the structure shown in this file with that of L11 shown in A.

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144. Kressler D, Bange G, Ogawa Y, Stjepanovic G, Bradatsch B, Pratte D, Amlacher S, Strauss D, Yoneda Y, Katahira J, Sinning I, Hurt E (2012). Synchronizing nuclear import of ribosomal proteins with ribosome assembly. Science 338(6107): 666-671. https://doi.org/10.1126/science.1226960

163. Calviño FR, Kharde S, Ori A, Hendricks A, Wild K, Kressler D, Bange G, Hurt E, Beck M, Sinning I (2015). Symportin 1 chaperones 5S RNP assembly during ribosome biogenesis by occupying an essential rRNA-binding site. Nat Commun 6: 6510. https://doi.org/10.1038/ncomms7510

164. Zheng J, Lang Y, Zhang Q, Cui D, Sun H, Jiang L, Chen Z, Zhang R, Gao Y, Tian W, Wu W, Tang J (2015). Structure of human MDM2 complexed with RPL11 reveals the molecular basis of p53 activation. Genes Dev 29(14): 1524-1534. https://doi.org/10.1101/gad.261792.115