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Related Experiment Video

Updated: Jul 26, 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 multienzyme complex with an intramolecular tunnel.

E W Miles1

  • 1Section on Enzyme Structure and Function, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda Maryland 20892-0830, USA. EdithM@intra.niddk.nih.gov

Chemical Record (New York, N.Y.)
|March 15, 2002
PubMed
Summary

Tryptophan synthase forms L-tryptophan using a hydrophobic tunnel to channel indole between enzyme subunits. This mechanism, confirmed by kinetics and structural studies, prevents intermediate escape and ensures efficient catalysis.

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Related Experiment Videos

Last Updated: Jul 26, 2026

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

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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
  • Structural Biology
  • Enzymology

Background:

  • Tryptophan synthase is a key enzyme in L-tryptophan biosynthesis.
  • Metabolic intermediates like indole are often channeled within enzymes to enhance efficiency and prevent diffusion.
  • Understanding enzyme architecture and reaction mechanisms is crucial for metabolic engineering and drug development.

Purpose of the Study:

  • To elucidate the structural basis of indole channeling in tryptophan synthase.
  • To investigate the role of the intramolecular tunnel in enzyme mechanism and substrate transfer.
  • To understand the conformational dynamics and inter-subunit communication within the tryptophan synthase complex.

Main Methods:

  • X-ray crystallography of the Salmonella typhimurium tryptophan synthase alpha2beta2 complex.
  • Rapid kinetic studies of wild-type and mutant enzymes.
  • Solution studies investigating ligand-induced conformational changes.

Main Results:

  • The crystal structure revealed an intramolecular hydrophobic tunnel connecting the alpha and beta active sites.
  • Kinetic data supported the proposed indole channeling mechanism through the tunnel.
  • Structural studies of enzyme-substrate intermediates showed dynamic conformational changes in the tunnel and active sites.
  • Ligand-induced conformational changes were observed, suggesting inter-subunit signaling.

Conclusions:

  • Tryptophan synthase utilizes a unique intramolecular tunnel for efficient indole channeling.
  • The enzyme's conformational switching between open and closed states couples catalytic reactions and prevents indole escape.
  • Structural and kinetic data provide strong evidence for a sophisticated channeling mechanism in multienzyme complexes.