1QDL

THE CRYSTAL STRUCTURE OF ANTHRANILATE SYNTHASE FROM SULFOLOBUS SOLFATARICUS

Summary for 1QDL

• Entry DOI: 10.2210/pdb1qdl/pdb
• Descriptor: PROTEIN (ANTHRANILATE SYNTHASE (TRPE-SUBUNIT)), PROTEIN (ANTHRANILATE SYNTHASE (TRPG-SUBUNIT)) (3 entities in total)
• Functional Keywords: tryptophan biosynthesis, anthranilate synthase, glutamine amidotransferase, allosteric interaction, lyase
• Biological source: Sulfolobus solfataricus; More
• Total number of polymer chains: 2
• Total formula weight: 69716.71

Authors

Knoechel, T.,Ivens, A.,Hester, G.,Gonzalez, A.,Bauerle, R.,Wilmanns, M.,Kirschner, K.,Jansonius, J.N. (deposition date: 1999-05-20, release date: 1999-08-18, Last modification date: 2024-02-14)

Primary citation

Knochel, T.,Ivens, A.,Hester, G.,Gonzalez, A.,Bauerle, R.,Wilmanns, M.,Kirschner, K.,Jansonius, J.N.
The crystal structure of anthranilate synthase from Sulfolobus solfataricus: functional implications.
Proc.Natl.Acad.Sci.USA, 96:9479-9484, 1999

PubMed Abstract: Anthranilate synthase catalyzes the synthesis of anthranilate from chorismate and glutamine and is feedback-inhibited by tryptophan. The enzyme of the hyperthermophile Sulfolobus solfataricus has been crystallized in the absence of physiological ligands, and its three-dimensional structure has been determined at 2.5-A resolution with x-ray crystallography. It is a heterotetramer of anthranilate synthase (TrpE) and glutamine amidotransferase (TrpG) subunits, in which two TrpG:TrpE protomers associate mainly via the TrpG subunits. The small TrpG subunit (195 residues) has the known "triad" glutamine amidotransferase fold. The large TrpE subunit (421 residues) has a novel fold. It displays a cleft between two domains, the tips of which contact the TrpG subunit across its active site. Clusters of catalytically essential residues are located inside the cleft, spatially separated from clustered residues involved in feedback inhibition. The structure suggests a model in which chorismate binding triggers a relative movement of the two domain tips of the TrpE subunit, activating the TrpG subunit and creating a channel for passage of ammonia toward the active site of the TrpE subunit. Tryptophan presumably blocks this rearrangement, thus stabilizing the inactive states of both subunits. The structure of the TrpE subunit is a likely prototype for the related enzymes 4-amino 4-deoxychorismate synthase and isochorismate synthase.

PubMed: 10449718
DOI: 10.1073/pnas.96.17.9479

Experimental method

X-RAY DIFFRACTION (2.5 Å)