An Unexpected Species Determined by X-ray Crystallography that May Represent an Intermediate in the Reaction Catalyzed by Quinolinate Synthase.

ABSTRACT: Quinolinic acid is a common intermediate in the biosynthesis of nicotinamide adenine dinucleotide and its derivatives in all organisms that synthesize the molecule de novo. In most prokaryotes, it is formed from the condensation of dihydroxyacetone phosphate (DHAP) and iminoaspartate (IA) by the action of quinolinate synthase (NadA). NadA contains a [4Fe-4S] cluster cofactor with a unique noncysteinyl-ligated iron ion (Fe_a), which is proposed to bind the hydroxyl group of an intermediate in its reaction to facilitate a dehydration step. However, direct evidence for this role in catalysis has yet to be provided, and the exact chemical mechanism that underlies this transformation remains elusive. Herein, we present a structure of NadA from Pyrococcus horikoshii (PhNadA) in

SUBMITTER: Esakova OA 

PROVIDER: S-EPMC7029380 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature