||p.730 left column top paragraph:"Ribosomes are large cellular ribonucleoprotein assemblies responsible for protein synthesis in all organisms. Bacterial ribosomes consist of two subunits with a combined molecular weight of ~2600 kD. The small ribosomal subunit is responsible for decoding the information encoded in mRNA, whereas peptide bond synthesis occurs at the large ribosomal subunit (ref 1). Although the core ribosomal function is preserved in all kingdoms of life, eukaryotic ribosomes are larger, ~4300 kD, and substantially more complex, comprising 45 additional proteins and two additional rRNAs (refs 2, 3). Although bacterial ribosome structure and function is well understood, thanks largely to experiments guided by atomic structures (ref 1), many aspects of eukaryotic ribosome function have remained elusive."