In the presence of high intracellular concentrations of tryptophan, only short transcripts of the trp operon are synthesized because of attenuation of transcription 5′ to the structural genes. This is mediated by the recognition of two Trp codons in the leader sequence. Explain what effect mutating these two codons to UAG stop codons would have on the regulation of the operon in the presence or absence of tryptophan.