Sandrine Ollagnier de Choudens
The Quinolinate synthase, NadA, is a [4Fe-4S]-containing enzyme that catalyzes the complex condensation between iminoaspartate (IA) and dihydroxyacetone phosphate (DHAP) forming quinolinic acid (QA). The Fe-S cluster, coordinated by three cysteine residues and one water molecule is essential for the activity. During the last years, we progressed extensively in the mechanism of the reaction catalysed by NadA using biochemical and structural approaches (identification of intermediates and evidence of two active site cavities). Currently, we aim at: (i) trapping the two substrates in the two active site cavities; (ii) understanding the condensation mechanism, (iii) unravelling the stereochemistry of the reaction.
Reaction catalyzed by NadA.