Biophysical characterization of the structure and flexibility of the E. Coli ribosome

Abstract

At the discovery of ribosomes by George Palade in 1955 in the first image of the subcellular environment, he described them as "a particulate component of small dimensions (100 to 150 [alpha]) and high density". Subsequently, the ribosome was shown to be the site of protein synthesis, or translation, and thus an essential macromolecular complex for all cells. Ribosomes can have variability from species to species, but the overall structure and function are conserved [66]. Ribosomes are named according to their sedimentation coefficients, a unit of density expressed in Svedbergs (abbreviated S). The three most studied and most prevalent ribosomes are the bacterial 70S, the eukaryotic 80S, and the 55S mitoribosome, which is present in the mitochondrion organelle. The bacterial ribosome serves as a target for many antibiotics and is a model system for investigating the structure and function of this "nanomachine". Despite variations in size, all ribosomes consist of a small and a large subunit that when bound together have an internal cavity that is divided into three sites, named A, P, or E site. The bacterial ribosome has a 30S small subunit, which consists of a 16S rRNA and 21 attached proteins, and a 50S large subunit that is made up of the 23S rRNA, 5S rRNA and 31 proteins. This dissertation discusses the 70S bacterial ribosome, other than when the 80S eukaryotic ribosome is specified.