The extension of polyphenylalanine and polylysine peptides on Escherichia coli ribosomes

Fluorescence techniques were used to examine aminoacyl-tRNA binding to Escherichia coli ribosomes and the subsequent extension of polyphenylalanine and polylysine nascent peptides. The results demonstrate that deacylated tRNA, an analogue of peptidyl-tRNA and puromycin (an analogue of aminoacyl-tRNA) can be bound simultaneously to the same ribosome. Moreover, the fluorescence properties of nascent polyphenylalanine and polylysine peptides with a fluorophore attached to their amino termini were determined and found to be quite different. This difference is reflected in the effects that erythromycin has in each case.