Catalysis and communication in two active sites of the ribosome

WCC 25

Rachel Green, ragreen@jhmi.edu, Department of Molecular Biology and Genetics and the Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205
Translation of the genetic code is mediated by the adaptor tRNA substrates and protein factors interacting with two distinct active sites in the RNA-rich functional centers of the ribosome. We are using mutant analysis coupled with pre-steady state kinetic approaches to decipher the molecular details of ribosome function in these active sites. Previous mutational analysis of the role of nucleotides in the large subunit catalytic center indicated that the universally conserved residues found there were most important for the role that they play in peptide release (and not in peptidyl transfer). Current studies are focused on the protein class I release factors (RF1 and RF2) and (1) how they interact with the large subunit active site to trigger the hydrolytic reaction of peptide release and (2) how their interactions with the decoding center of the small subunit are critical to this function.