FACTOR-FREE AND ENERGY-FREE PEPTIDE-SYNTHESIS PROMOTED BY AROMATIC TERTIARY-AMINES INCLUDING NUCLEIC ACID-RELATED COMPOUNDS

We have already reported a novel, in vitro translation system, promote d by pyridine instead of the usual protein factors and energy sources, which consists of only salt-washed ribosomes from Escherichia coil, a minoacyl-tRNA, a template RNA, Na+ and Mg2+ cations, and 40-60% pyridi ne [Nitta et al. (1994) J. Biochem, 115, 803-807 and the accompanying paper]. Here we show that in this system, pyridine can be replaced not only by pyridine derivatives but also by nucleobases or nucleosides, demonstrating that any compound harboring an aromatic tertiary amine w ithin the molecule possesses such promoting activity. These compounds may serve to assist the peptide bond formation catalyzed by peptidyltr ansferase within ribosomes. The finding that nucleobases and nucleosid es can play such a role in this reaction implies the possibility that these compounds were directly involved in the premordial translation s ystem.