2xux | pdb_00002xux

tRNA translocation on the 70S ribosome: the post- translocational translocation intermediate TI(POST)

spinqualitylabelsall models 2xux, resolution 7.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xux is a 32 chain structure with sequence from Escherichia coli and Thermus thermophilus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 2xuy, 1rqt, 2wdi, 2v47, 2xg0, 2xtg, 2jl6, 2xg2, 2wdl, 2x9s, 1yl3, 1rqs, 1giy, 2wro, 2xqe, 2wrr, 2bcw, 1wki, 1ctf, 2b9n, 2wh4, 2wh2, 1rqv, 2b9p, 1rqu, 2v49, 2jl8, 2b66, 1v8q, 2j03, 2j01, 2wdn, 1gd8, 2x9u, 2wdj Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed The elongation cycle of protein synthesis involves the delivery of aminoacyl-transfer RNAs to the aminoacyl-tRNA-binding site (A site) of the ribosome, followed by peptide-bond formation and translocation of the tRNAs through the ribosome to reopen the A site. The translocation reaction is catalysed by elongation factor G (EF-G) in a GTP-dependent manner. Despite the availability of structures of various EF-G-ribosome complexes, the precise mechanism by which tRNAs move through the ribosome still remains unclear. Here we use multiparticle cryoelectron microscopy analysis to resolve two previously unseen subpopulations within Thermus thermophilus EF-G-ribosome complexes at subnanometre resolution, one of them with a partly translocated tRNA. Comparison of these substates reveals that translocation of tRNA on the 30S subunit parallels the swivelling of the 30S head and is coupled to unratcheting of the 30S body. Because the tRNA maintains contact with the peptidyl-tRNA-binding site (P site) on the 30S head and simultaneously establishes interaction with the exit site (E site) on the 30S platform, a novel intra-subunit 'pe/E' hybrid state is formed. This state is stabilized by domain IV of EF-G, which interacts with the swivelled 30S-head conformation. These findings provide direct structural and mechanistic insight into the 'missing link' in terms of tRNA intermediates involved in the universally conserved translocation process. Head swivel on the ribosome facilitates translocation by means of intra-subunit tRNA hybrid sites.,Ratje AH, Loerke J, Mikolajka A, Brunner M, Hildebrand PW, Starosta AL, Donhofer A, Connell SR, Fucini P, Mielke T, Whitford PC, Onuchic JN, Yu Y, Sanbonmatsu KY, Hartmann RK, Penczek PA, Wilson DN, Spahn CM Nature. 2010 Dec 2;468(7324):713-6. PMID:21124459 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures

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