Figure 1.

Positional effect of AGAAGA codons in the synthesis of β-gal. (A) In vitro transcription–translation reactions deficient in Pth activity, not supplemented with tRNA and carried out as described in ‘Materials and Methods' section, were directed by: placZ (a); placZ2-3AGAAGA (b); placZ3-4AGAAGA (c); placZ4-5AGAAGA (d); placZ5-6AGAAGA (e); placZ6-7AGAAGA (f); placZ7-8AGAAGA (g). After 1 h incubation, samples were processed for autoradiography as described in ‘Materials and Methods’ section. The mobility of β-galactosidase (β-gal) and β-lactamase (β-lac) is indicated. β-gal absolute radioactivity levels indicated as electronic density values (pixels; shown below each lane) were quantified as indicated in ‘Materials and Methods’ section. (B) β-gal synthesis from the AGAAGA constructs was plotted against the AGAAGA codon position.