Remnants of an ancient pathway to L-phenylalanine and L-tyrosine in enteric bacteria: Evolutionary implications and biotechnological impact. [Escherichia coli; Salmonella typhimurium; Neurospora crassa]

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Applied and Environmental Microbiology; (USA)

OSTI ID:5961577

Bonner, C A; Fischer, R S; Ahmad, S; Jensen, R A ^[1]

---

1. Univ. of Florida, Gainesville (USA)

The pathway construction for biosynthesis of aromatic amino acids in Escherichia coli is atypical of the phylogenetic subdivision of gram-negative bacteria to which it belongs. Related organisms possess second pathways to phenylalanine and tyrosine which depend upon the expression of a monofunctional chorismate mutase (CM-F) and cyclohexadienyl dehydratase (CDT). Some enteric bacteria, unlike E. coli, possess either CM-F or CDT. These essentially cryptic remnants of an ancestral pathway can be a latent source of biochemical potential under certain conditions. As one example of advantageous biochemical potential, the presence of CM-F in Salmonella typhimurium increases the capacity for prephenate accumulation in a tyrA auxotroph. We report the finding that a significant fraction of the latter prephenate is transaminated to L-arogenate. The tyrA19 mutant is now the organism of choice for isolation of L-arogenate, uncomplicated by the presence of other cyclohexadienyl products coaccumulated by a Neurospora crassa mutant that had previously served as the prime biological source of L-arogenate. Prephenate aminotransferase activity was not conferred by a discrete enzyme, but rather was found to be synonymous with the combined activities of aspartate aminotransferase (aspC), aromatic aminotransferase (tyrB), and branched-chain aminotransferase (ilvE).

• OSTI ID: 5961577
• Journal Information: Applied and Environmental Microbiology; (USA), Vol. 56:12; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
BIOSYNTHESIS
BACTERIA
METABOLISM
BIOLOGICAL PATHWAYS
BIOTECHNOLOGY
ENZYME ACTIVITY
ESCHERICHIA COLI
NEUROSPORA
PHENYLALANINE
SALMONELLA TYPHIMURIUM
TYROSINE
CARBOXYLIC ACIDS
EUMYCOTA
FUNGI
HYDROXY ACIDS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PLANTS
SALMONELLA
SYNTHESIS
550500* - Metabolism