7p4m

Structure of the quinolinate synthase Y107F variant in an empty open form

spinqualitylabelsall models 7p4m, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7p4m is a 1 chain structure with sequence from Thermotoga maritima MSB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.55Å Ligands: CL, F3S, SF4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function NADA_THEMA Catalyzes the condensation of iminoaspartate with dihydroxyacetone phosphate to form quinolinate (By similarity). Publication Abstract from PubMed Quinolinate synthase, also called NadA, is a [4Fe-4S]-containing enzyme that uses what is probably the oldest pathway to generate quinolinic acid (QA), the universal precursor of the biologically essential cofactor nicotinamide adenine dinucleotide (NAD). Its synthesis comprises the condensation of dihydroxyacetone phosphate (DHAP) and iminoaspartate (IA), which involves dephosphorylation, isomerization, cyclization, and two dehydration steps. The convergence of the three homologous domains of NadA defines a narrow active site that contains a catalytically essential [4Fe-4S] cluster. A tunnel, which can be opened or closed depending on the nature (or absence) of the bound ligand, connects this cofactor to the protein surface. One outstanding riddle has been the observation that the so far characterized active site is too small to bind IA and DHAP simultaneously. Here, we have used site-directed mutagenesis, X-ray crystallography, functional analyses, and molecular dynamics simulations to propose a condensation mechanism that involves the transient formation of a second active site cavity to which one of the substrates can migrate before this reaction takes place. Transient Formation of a Second Active Site Cavity during Quinolinic Acid Synthesis by NadA.,Basbous H, Volbeda A, Amara P, Rohac R, Martin L, Ollagnier de Choudens S, Fontecilla-Camps JC ACS Chem Biol. 2021 Oct 5. doi: 10.1021/acschembio.1c00541. PMID:34609124 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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