Studies of the dynamics and mechanism of protein synthesis

The proteins in a living cell are synthesized on a large bipartite RNP complex termed the ribosome. This particle translates the genetic information from mRNAs into the amino acid sequence of the proteins and is one of the main targets of antibiotics. Two aminoacyl-tRNAs bind according to the information on mRNA and the peptidyl transferase polymerises the amino acids yielding proteins. Peptide bond formation, the covalent linkage of amino acids during mRNA translation, is among the most fundamental biochemical transformations in nature, and is the principal catalytic activity of ribosomes. This is a very dynamic process as the mRNA and tRNAs are transported through the ribosome. The recent x-ray structures of ribosomal subunits have revealed important informations about the active sites but cannot capture ribosomal dynamics. Therefore, we will investigate structural changes in rRNAs during protein synthesis by chemical probing techniques. The enzymatic activity (peptidyl transferase) is localized on the large subunit of the ribosome. The mechanism of this reaction is currently debated intensively. By using modified substrates we will investigate the hypotheses that catalysis is aided by magnesium ions. In addition, the significance of adjacent functional groups for the chemical reaction will be evaluated.

The proteins in a living cell are synthesized on a large bipartite RNP complex termed the ribosome. This particle translates the genetic information from mRNAs into the amino acid sequence of the proteins and is one of the main targets of antibiotics. Two aminoacyl-tRNAs bind according to the information on mRNA and the peptidyl transferase polymerises the amino acids yielding proteins. Peptide bond formation, the covalent linkage of amino acids during mRNA translation, is among the most fundamental biochemical transformations in nature, and is the principal catalytic activity of ribosomes. This is a very dynamic process as the mRNA and tRNAs are transported through the ribosome. The recent x-ray structures of ribosomal subunits have revealed important informations about the active sites but cannot capture ribosomal dynamics. Therefore, we will investigate structural changes in rRNAs during protein synthesis by chemical probing techniques. The enzymatic activity (peptidyl transferase) is localized on the large subunit of the ribosome. The mechanism of this reaction is currently debated intensively. By using modified substrates we will investigate the hypotheses that catalysis is aided by magnesium ions. In addition, the significance of adjacent functional groups for the chemical reaction will be evaluated.