30 October 2009
Vol 326, Issue 5953

About The Cover

Cover image expansion

COVER Crystal structures of the 70S ribosome from the bacterium Thermus thermophilus in complex with translation elongation factors Tu (EF-Tu) and G (EF-G). During protein synthesis, EF-Tu (in periwinkle blue, center) delivers an aminoacyl transfer RNA (green) to the ribosome for each amino acid indicated by the messenger RNA. As the polypeptide chain grows, EF-G (in green at top right) helps move the mRNA and tRNAs through the ribosome. See pages 688 and 694. Image: Larissa Ulisko, Rebecca Voorhees, Martin Schmeing