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Related Concept Videos

Repressible Operon: trp Operon01:21

Repressible Operon: trp Operon

The trp operon in Escherichia coli exemplifies a repressible operon. It regulates the synthesis of tryptophan through repressor-mediated transcriptional control and attenuation. This dual regulatory mechanism ensures tryptophan biosynthesis occurs only when needed, conserving cellular resources.Structure of the trp OperonThe trp operon consists of five structural genes (trpE, trpD, trpC, trpB, and trpA) that encode enzymes for tryptophan biosynthesis. These genes are transcribed as a single...
Amino Acid Biosynthetic Pathways01:29

Amino Acid Biosynthetic Pathways

Amino acid biosynthesis is essential for cell growth, protein synthesis, and metabolic regulation. Cells generate essential and non-essential amino acids from metabolic intermediates to sustain vital biological functions. These intermediates originate from key metabolic pathways: glycolysis, the tricarboxylic acid (TCA) cycle, and the pentose phosphate pathway. Important precursors include α-ketoglutarate, pyruvate, oxaloacetate, phosphoenolpyruvate, and erythrose-4-phosphate, which provide...
Transcription Attenuation in Prokaryotes02:42

Transcription Attenuation in Prokaryotes

Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure.  Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
American Trypanosomiasis01:22

American Trypanosomiasis

Chagas disease, or American trypanosomiasis, is a vector-borne parasitic infection caused by Trypanosoma cruzi, a flagellated protozoan (kinetoplastid) of the family Trypanosomatidae. The disease is endemic in Latin America, although cases are increasingly reported worldwide due to human migration. Transmission most commonly occurs when feces of infected triatomine bugs contaminate bite wounds or mucosal surfaces; additional routes include congenital, transfusional, transplant-related, and oral...
Production of Pharmaceuticals01:30

Production of Pharmaceuticals

Industrial insulin production uses genetically engineered E. coli expressing a proinsulin gene controlled by a tryptophan promoter and containing a methionine linker for later cleavage. The cells also carry ampicillin resistance for selective growth. Seed cultures are stored at −80 °C and production begins by thawing a small amount to inoculate starter cultures, which are progressively scaled to a 50,000-L bioreactor. In the bioreactor, E. coli grow in nutrient-rich media under sterile, tightly...

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Related Experiment Video

Updated: Jun 23, 2026

PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase
09:31

PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase

Published on: September 26, 2020

Tryptophan synthase: a mine for enzymologists.

Samanta Raboni1, Stefano Bettati, Andrea Mozzarelli

  • 1Department of Biochemistry and Molecular Biology, University of Parma, Viale G P Usberti 23/A, Parma, Italy.

Cellular and Molecular Life Sciences : CMLS
|April 24, 2009
PubMed
Summary

Tryptophan synthase, a key enzyme in tryptophan biosynthesis, uses distinct alpha and beta active sites that communicate through conformational changes. Studies reveal how indole is channeled and how mutations impact enzyme function.

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Chemical Modification of the Tryptophan Residue in a Recombinant Ca2+-ATPase N-domain for Studying Tryptophan-ANS FRET
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Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol
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Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol

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Related Experiment Videos

Last Updated: Jun 23, 2026

PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase
09:31

PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase

Published on: September 26, 2020

Chemical Modification of the Tryptophan Residue in a Recombinant Ca2+-ATPase N-domain for Studying Tryptophan-ANS FRET
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Chemical Modification of the Tryptophan Residue in a Recombinant Ca2+-ATPase N-domain for Studying Tryptophan-ANS FRET

Published on: October 9, 2021

Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol
08:33

Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol

Published on: September 21, 2021

Area of Science:

  • Biochemistry
  • Enzymology
  • Molecular Biology

Background:

  • Tryptophan synthase is a crucial enzyme complex responsible for the final steps of tryptophan biosynthesis.
  • It is a pyridoxal 5'-phosphate-dependent alpha(2)beta(2) complex found in bacteria, plants, and fungi.
  • Decades of research have elucidated its complex structure, dynamics, and function.

Purpose of the Study:

  • To summarize key findings from over 40 years of research on tryptophan synthase.
  • To highlight the communication mechanisms between the alpha and beta active sites.
  • To underscore the role of enzyme structure and dynamics in its catalytic activity and regulation.

Main Methods:

  • Structural analysis of the tryptophan synthase complex.
  • Dynamic studies to understand conformational changes.
  • Functional assays using naturally occurring and genetically engineered mutants.

Main Results:

  • Alpha and beta active sites are spatially separated but communicate through conformational states.
  • Indole is formed at the alpha site and channeled to the beta site for tryptophan synthesis.
  • Mutational studies identified specific amino acid roles in enzyme function and regulation.

Conclusions:

  • Tryptophan synthase exemplifies the interplay between chemical processes and conformational energy landscapes.
  • Its intricate communication pathways and substrate channeling provide insights into enzyme mechanisms.
  • The enzyme serves as a model system for understanding protein dynamics and allosteric regulation.