5KTT

Crystal structure of Pyrococcus horikoshii quinolinate synthase (NadA) with bound L-malate and Fe4S4 cluster

Summary for 5KTT

• Entry DOI: 10.2210/pdb5ktt/pdb
• Related: 5KTM 5KTN 5KTO 5KTP 5KTR 5KTS
• Descriptor: Quinolinate synthase A, IRON/SULFUR CLUSTER, (2S)-2-hydroxybutanedioic acid, ... (4 entities in total)
• Functional Keywords: dehydratase, iron-sulfur cluster, substrate analog complex, biosynthetic enzyme, transferase
• Biological source: Pyrococcus horikoshii (strain ATCC 700860 / DSM 12428 / JCM 9974 / NBRC 100139 / OT-3)
• Total number of polymer chains: 1
• Total formula weight: 35068.16

Authors

Fenwick, M.K.,Ealick, S.E. (deposition date: 2016-07-12, release date: 2016-07-27, Last modification date: 2023-10-04)

Primary citation

Fenwick, M.K.,Ealick, S.E.
Crystal Structures of the Iron-Sulfur Cluster-Dependent Quinolinate Synthase in Complex with Dihydroxyacetone Phosphate, Iminoaspartate Analogues, and Quinolinate.
Biochemistry, 55:4135-4139, 2016

PubMed Abstract: The quinolinate synthase of prokaryotes and photosynthetic eukaryotes, NadA, contains a [4Fe-4S] cluster with unknown function. We report crystal structures of Pyrococcus horikoshii NadA in complex with dihydroxyacetone phosphate (DHAP), iminoaspartate analogues, and quinolinate. DHAP adopts a nearly planar conformation and chelates the [4Fe-4S] cluster via its keto and hydroxyl groups. The active site architecture suggests that the cluster acts as a Lewis acid in enediolate formation, like zinc in class II aldolases. The DHAP and putative iminoaspartate structures suggest a model for a condensed intermediate. The ensemble of structures suggests a two-state system, which may be exploited in early steps.

PubMed: 27404889
DOI: 10.1021/acs.biochem.6b00626

Experimental method

X-RAY DIFFRACTION (1.5 Å)