Structure and kinetics of indole-3-glycerol phosphate synthase from Pseudomonas aeruginosa: Decarboxylation is not essential for indole formation.

ABSTRACT: In tryptophan biosynthesis, the reaction catalyzed by the enzyme indole-3-glycerol phosphate synthase (IGPS) starts with a condensation step in which the substrate's carboxylated phenyl group makes a nucleophilic attack to form the pyrrole ring of the indole, followed by a decarboxylation that restores the aromaticity of the phenyl. IGPS from Pseudomonas aeruginosa has the highest turnover number of all characterized IGPS enzymes, providing an excellent model system to test the necessity of the decarboxylation step. Since the 1960s, this step has been considered to be mechanistically essential based on studies of the IGPS-phosphoribosylanthranilate isomerase fusion protein from Escherichia coli Here, we present the crystal structure of P. aeruginosa IGPS in complex wit

SUBMITTER: Soderholm A 

PROVIDER: S-EPMC7681013 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature