Structure Short Article Structures of Yeast 80S Ribosome-tRNA Complexes in the Rotated and Nonrotated Conformations Egor Svidritskiy,1,4 Axel F. Brilot,2,4 Cha San Koh,1 Nikolaus Grigorieff,2,3,5,* and Andrei A. Korostelev1,5,* 1RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA 2Department of Biochemistry, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA 3Janelia Farm Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA 4Co-first author 5Co-senior author *Correspondence:
[email protected] (N.G.),
[email protected] (A.A.K.) http://dx.doi.org/10.1016/j.str.2014.06.003 SUMMARY upstream of the open reading frame (Dalgarno and Shine, 1973) forms base-pairing interactions with the complimentary The structural understanding of eukaryotic translation anti-Shine-Dalgarno region of the ribosomal 16S RNA. The for- lags behind that of translation on bacterial ribosomes. mation of this specific contact results in positioning of the down- Here, we present two subnanometer resolution struc- stream AUG start codon in the P site of the small 30S subunit, tures of S. cerevisiae 80S ribosome complexes thus determining the open reading frame of the mRNA for trans- formed with either one or two tRNAs and bound in lation (Kaminishi et al., 2007; Korostelev et al., 2007; Yusupova response to an mRNA fragment containing the Kozak et al., 2006). By contrast, initiation in eukaryotes depends on at least a dozen initiation factors (Aitken and Lorsch, 2012).