Premium
Structural insights into cognate versus near‐cognate discrimination during decoding
Author(s) -
Agirrezabala Xabier,
Schreiner Eduard,
Trabuco Leonardo G,
Lei Jianlin,
OrtizMeoz Rodrigo F,
Schulten Klaus,
Green Rachel,
Frank Joachim
Publication year - 2011
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2011.58
Subject(s) - cognate , library science , biology , computer science , philosophy , linguistics
The structural basis of the tRNA selection process is investigated by cryo‐electron microscopy of ribosomes programmed with UGA codons and incubated with ternary complex (TC) containing the near‐cognate Trp‐tRNA Trp in the presence of kirromycin. Going through more than 350 000 images and employing image classification procedures, we find ∼8% in which the TC is bound to the ribosome. The reconstructed 3D map provides a means to characterize the arrangement of the near‐cognate aa‐tRNA with respect to elongation factor Tu (EF‐Tu) and the ribosome, as well as the domain movements of the ribosome. One of the interesting findings is that near‐cognate tRNA's acceptor stem region is flexible and CCA end becomes disordered. The data bring direct structural insights into the induced‐fit mechanism of decoding by the ribosome, as the analysis of the interactions between small and large ribosomal subunit, aa‐tRNA and EF‐Tu and comparison with the cognate case (UGG codon) offers clues on how the conformational signals conveyed to the GTPase differ in the two cases.