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Updated: Aug 11, 2026
08:53
Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092
Published on: October 2, 2017
The crystal structure of anthranilate synthase from Sulfolobus solfataricus: functional implications
1Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
Summary
Anthranilate synthase from Sulfolobus solfataricus was structurally analyzed. Its novel fold and domain movement mechanism reveal how tryptophan inhibits enzyme activity.
Area of Science:
- Enzymology
- Structural Biology
- Biochemistry
Background:
- Anthranilate synthase synthesizes anthranilate from chorismate and glutamine.
- This enzyme is crucial for tryptophan biosynthesis and is subject to feedback inhibition by tryptophan.
- Understanding its structure is key to elucidating its catalytic mechanism and regulation.
Purpose of the Study:
- To determine the three-dimensional structure of anthranilate synthase from the hyperthermophile Sulfolobus solfataricus.
- To elucidate the structural basis for enzyme activity and feedback inhibition by tryptophan.
Main Methods:
- X-ray crystallography was employed to determine the enzyme's structure at 2.5-Å resolution.
- The enzyme was crystallized in the absence of physiological ligands.
Main Results:
- The enzyme is a heterotetramer composed of anthranilate synthase (TrpE) and glutamine amidotransferase (TrpG) subunits.
- The TrpE subunit possesses a novel fold with two domains, featuring a cleft containing catalytic residues.
- A structural model suggests chorismate binding induces domain movement in TrpE, activating TrpG and forming an ammonia channel, while tryptophan likely inhibits this process.
Conclusions:
- The determined structure provides insights into the catalytic mechanism and allosteric regulation of anthranilate synthase.
- The TrpE subunit structure may serve as a model for related enzymes like 4-amino 4-deoxychorismate synthase and isochorismate synthase.
- This study reveals a potential mechanism for feedback inhibition involving domain rearrangement.
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