for the attenuation of the trp operon which regions of the l

for the attenuation of the trp operon which regions of the leader sequence form a hairpin when trp levels are just enough

Solution

Answer : The trp operon attenuation mechanism uses signals encoded in four sequences within a 162 nucleotide
leader region at the 5 end of the mRNA, preceding the initiation codon of the first gene Within the leader lies a region known as the attenuator, made up of sequences 3 and 4. These sequences base-pair to form a GqC-rich stem-and-loop structure closely followed by a series of U residues. The attenuator structure acts as a transcription terminator. Sequence 2 is an alternative complement for sequence 3. If sequences 2 and 3 base-pair, the attenuator
structure cannot form and transcription continues into the trp biosynthetic genes; the loop formed by the pairing of sequences 2 and 3 does not obstruct transcription.