2FN1: Crystal Structures Of Yersinia Enterocolitica Salicylate Synthase (Irp9) In Complex With The Reaction Products Salicylate And Pyruvate

Citation:
Abstract
The salicylate synthase, Irp9, from Yersinia enterocolitica is involved in the biosynthesis of the siderophore yersiniabactin. It is a bifunctional enzyme that forms salicylate and pyruvate from chorismate and water via the intermediate isochorismate. Here we report the first crystal structure of Irp9 and also of its complex with the reaction products salicylate and pyruvate at 1.85 A and 2.1 A resolution, respectively. Like other members of the chorismate-utilizing enzyme family, e.g. the TrpE subunit of anthranilate synthase and the PabB subunit of 4-amino-4-deoxychorismate synthase, Irp9 has a complex alpha/beta fold. The crystal structure of Irp9 contains one molecule each of phosphate and acetate derived from the crystallization buffer. The Irp9-products complex structure was obtained by soaking chorismate into Irp9, demonstrating that the enzyme is still catalytically active in the crystal. Both structures contain Mg(2+) in the active site. There is no evidence of the allosteric tryptophan binding site found in TrpE and PabB. Mutagenesis of Glu240, His321 and Tyr372 provided some insight into the mechanism of the two transformations catalyzed by Irp9. Knowledge of the structure of Irp9 will guide the search for potent inhibitors of salicylate formation, and hence of bacterial iron uptake, which is directly related to the virulence of Yersinia.
PDB ID: 2FN1Download
MMDB ID: 37781
PDB Deposition Date: 2006/1/10
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 2FN1: dimeric; determined by author and by software (PISA)
Molecular Components in 2FN1
Label Count Molecule
Proteins (2 molecules)
2
Salicylate Synthetase, Irp9
Molecule annotation
Chemicals (6 molecules)
1
2
2
2
3
2
* Click molecule labels to explore molecular sequence information.

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