1qdl
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THE CRYSTAL STRUCTURE OF ANTHRANILATE SYNTHASE FROM SULFOLOBUS SOLFATARICUS
OverviewOverview
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.
About this StructureAbout this Structure
1QDL is a Protein complex structure of sequences from Sulfolobus solfataricus. Active as Anthranilate synthase, with EC number 4.1.3.27 Full crystallographic information is available from OCA.
ReferenceReference
The crystal structure of anthranilate synthase from Sulfolobus solfataricus: functional implications., Knochel T, Ivens A, Hester G, Gonzalez A, Bauerle R, Wilmanns M, Kirschner K, Jansonius JN, Proc Natl Acad Sci U S A. 1999 Aug 17;96(17):9479-84. PMID:10449718
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