The long term goals of this research involve modification of the peptidyltransferase (PTC) center in
bacterial ribosomes to enable the incorporation of very unusual amino acids not recognized by wild-
type ribosomes. In recent years, we have described the selection of modified ribosomes and their use
in incorporating D-amino acids, beta amino acids, dipeptides and dipeptidomimetric cassettes into
proteins. During the four years of proposed research, the focus of efforts will be on the selection of
ribosomes capable of introducing phosphorylated and glycosylated amino acids into specific proteins.
The utility of this approach will be explored by analyzing the altered function of proteins into which
phosphates and carbohydrates have been introduced, and by expressing a phosphorylated DNA
binding protein in E. coli.