Novel mutations in the pheA gene of Escherichia coli K-12 which result in highly feedback inhibition-resistant variants of chorismate mutase/prephenate dehydratase
Article Abstract:
The pheA gene of Escherichia coli encodes the bifunctional enzyme chorismate mutase/prephenate dehydratase which is subject to feedback inhibition by phenylalanine. A synthetic pheA gene was constructed on plasmid pJN302 to allow its constitutive expression. However, a mutation at codon 338 resulted in the formation of a mutant resistant to phenylalanine inhibition. Nitrous acid treatment of pJN302 resulted in the formation of four other mutants which were also resistant to inhibition. In all cases, the mutation was at codons 304 to 310, a region not previously implicated in inhibition sensitivity. Activities of the mutant enzymes were characterized.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 1992
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Feedback inhibition of chorismate mutase/prephenate dehydrogenase (TyrA) of Escherichia coli: Generation and characterization of tyrosine-insensitive mutants
Article Abstract:
Different mutated TyrA proteins is generated and characterized to understand the feedback inhibition mechanism of the Escherichia coli chorismate mutase/prephenate dehydrogenase. Analyses of the DNA sequences of the tyrA genes revealed that tyrA(super fbr) contained amino acid substitutions either at Tyr263 or at residues 354 to 357, indicating that these two sites are involved in the feedback inhibition by tyrosine.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 2005
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Melanin-based high-throughput screen for L-tyrosine production in Escherichia coli
Article Abstract:
A simple, high-throughput screen is developed for identifying bacterial strains capable of L-tyrosine production. A strong linear correlation is observed between extracellular L-tyrosine content and melanin formation by using this new method.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 2008
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