Inhibition of polyphenylalanine formation by tRNA prepared from Escherichia coli cells starved for amino acids

Abstract

tRNA prepared from Escherichia coli cells starved for amino acids (“amino acid-starved” tRNA) exhibits normal phenylalanine acceptance and a reduced capacity to form polyphenylalanine in a ribosomal system dependent on polyuridylic acid and tRNA. The reduced capacity to form polyphenylalanine is due to an inhibitor contaminating “amino acid-starved” tRNA preparations. The polyphenylalanine formed in ribosomal systems containing “amino acid-starved” tRNA is attached mainly to short polysomes and 70-S particles. “Amino acid-starved” tRNA induces also the formation of shorter polysomes in the polyuridylic acid-dependent phenylalanyl-tRNA-binding reaction. Normal polysome formation can be restored by the addition of tRNA prepared from non-starved logarithmically growing cells.