Ribosome Rocks

If we are to talk about molecules of life, the ribosome, made of ribosomal RNA (rRNA) and protein, is a key: it stands at the junction between information and action, i.e. between nucleic acids and proteins. It is an extraordinarily sophisticated machine that takes the information present in mRNA and uses it to build proteins, containing over 250K atoms, and measuring more than 200 in every direction. It consists of two units: the small ribosomal subunit (30S that performs the decoding of genetic information during translation and the large ribosomal subunit (50S) that forms the peptide bonds. This structure has been under biochemical and genetic research for the last forty years, but it is in the last two years that by means of crystallographic analysis, “the pace of progress has been breathtaking”[1]. To date, Ban and his group have solved the structure of the large subunit at 2.4Å[2], two groups have solved the structure of the small unit for two different organisms at 3Å and 3.3Å [3, 4] and the structure of the intact 70S ribosome complexed with tRNAs and mRNA has been solved at 5.5Å [5], not yet at atomic resolution. Translation uses the genetic information in the messenger RNA (mRNA) to synthesize proteins. Transfer RNAs (tRNAs) are charged with an amino acid and brought to the ribosome, where they are paired with the corresponding trinucleotide codon in mRNA. The amino acid is attached to the nascent