What is the Gene Responsible for Attenuation in the Trp

Question

What is the gene responsible for attenuation in the trp operon?
A) trpL
B) trpR
C) trpD
D) trpC

Accepted Answer

The trpL gene encodes a leader peptide that plays a role in attenuation, which is the process of premature termination of transcription in the trp operon. When there are high levels of tryptophan (the end product of the trp operon), the trpL leader peptide is synthesized, which allows the mRNA to form a hairpin loop structure that causes RNA polymerase to prematurely terminate transcription. This mechanism ensures that the cell does not waste energy producing tryptophan when it is already abundant in the environment. The other choices (trpR, trpD, and trpC) are not directly involved in attenuation.