Corynebacterium glutamicum Contains 3-Deoxy-D-Arabino-Heptulosonate 7-Phosphate Synthases That Display Novel Biochemical Features

3-Deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase (EC 2.5.1.54) catalyzes the first step of the shikimate pathway that finally leads to the biosynthesis of aromatic amino acids phenylalanine (Phe), tryptophan (Trp), and tyrosine (Tyr). In Corynebacterium glutamicum ATCC 13032, two chromoso...

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Bibliographic Details
Published in:Applied and Environmental Microbiology 2008-09, Vol.74 (17), p.5497-5503
Main Authors: Liu, Ya-Jun, Li, Pan-Pan, Zhao, Ke-Xin, Wang, Bao-Jun, Jiang, Cheng-Ying, Drake, Harold L, Liu, Shuang-Jiang
Format: Article
Language:English
Subjects:
3-Deoxy-7-Phosphoheptulonate Synthase - drug effects
3-Deoxy-7-Phosphoheptulonate Synthase - genetics
3-Deoxy-7-Phosphoheptulonate Synthase - metabolism
Amino acids
Amino Acids, Aromatic - biosynthesis
Bacteria
Bacterial Proteins - drug effects
Bacterial Proteins - genetics
Bacterial Proteins - metabolism
Bacteriology
Biochemistry
Biological and medical sciences
Chromosomes
Cloning, Molecular
Corynebacterium glutamicum
Corynebacterium glutamicum - enzymology
Corynebacterium glutamicum - genetics
Corynebacterium glutamicum - metabolism
DNA, Bacterial - genetics
Electrophoresis, Gel, Two-Dimensional
Escherichia coli - enzymology
Escherichia coli - metabolism
Feedback, Physiological
Fundamental and applied biological sciences. Psychology
Gene Deletion
Genes
Genes, Bacterial
Genetic Complementation Test
Metals - pharmacology
Microbiology
Phenotype
Phosphates
Physiology and Biotechnology
Plasmids
Reverse Transcriptase Polymerase Chain Reaction
RNA, Bacterial - genetics
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Summary:3-Deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase (EC 2.5.1.54) catalyzes the first step of the shikimate pathway that finally leads to the biosynthesis of aromatic amino acids phenylalanine (Phe), tryptophan (Trp), and tyrosine (Tyr). In Corynebacterium glutamicum ATCC 13032, two chromosomal genes, NCgl0950 (aroF) and NCgl2098 (aroG), were located that encode two putative DAHP synthases. The deletion of NCgl2098 resulted in the loss of the ability of C. glutamicum RES167 (a restriction-deficient strain derived from C. glutamicum ATCC 13032) to grow in mineral medium; however, the deletion of NCgl0950 did not result in any observable phenotypic alteration. Analysis of DAHP synthase activities in the wild type and mutants of C. glutamicum RES167 indicated that NCgl2098, rather than NCgl0950, was involved in the biosynthesis of aromatic amino acids. Cloning and expression in Escherichia coli showed that both NCgl0950 and NCgl2098 encoded active DAHP synthases. Both the NCgl0950 and NCgl2098 DAHP synthases were purified from recombinant E. coli cells and characterized. The NCgl0950 DAHP synthase was sensitive to feedback inhibition by Tyr and, to a much lesser extent, by Phe and Trp. The NCgl2098 DAHP synthase was slightly sensitive to feedback inhibition by Trp, but not sensitive to Tyr and Phe, findings that were in contrast to the properties of previously known DAHP synthases from C. glutamicum subsp. flavum. Both Co²⁺ and Mn²⁺ significantly stimulated the NCgl0950 DAHP synthase's activity, whereas Mn²⁺ was much more stimulatory than Co²⁺ to the NCgl2098 DAHP synthase's activity.
ISSN:0099-2240
1098-5336
1098-6596
DOI:10.1128/AEM.00262-08