Fig. 3A: Attenuation in the Trp Operon of Escherichia coli: Excess Tryptophan

When excess tryptophan is available, there is a rapid translation of the early trp leader mRNA enabling domain 2 to pair with domain 1 and form a pause loop. The ribosome pauses at a stop codon (arrow) causing domain 3 to pair with domain 4 and form a terminator loop. Transcription of the remainder of the trp operon is terminated. Rapid initial translation is able to occur with excess tryptophan present because there is a sufficient quantity of Trp tRNA available to translate the two Trp codons (asterisks).

Illustration of Attenuation in the Trp Operon of Escherichia coli: Excess Tryptophan.jpg by Gary E. Kaiser, Ph.D.
Professor of Microbiology, The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at https://cwoer.ccbcmd.edu/science/microbiology/index_gos.html.

Creative Commons License

Last updated: September, 2018
Please send comments and inquiries to Dr. Gary Kaiser