pH Dependency of the reactions catalyzed by chorismate mutase-prephenate dehydrogenase from Escherichia coli

Biochemistry ◽  
1991 ◽  
Vol 30 (31) ◽  
pp. 7777-7782 ◽  
Author(s):  
Joanne Turnbull ◽  
W. W. Cleland ◽  
John F. Morrison
Keyword(s):  
Escherichia Coli ◽  
Chorismate Mutase ◽  
Prephenate Dehydrogenase ◽  
Ph Dependency

scholarly journals Feedback Inhibition of Chorismate Mutase/Prephenate Dehydrogenase (TyrA) of Escherichia coli: Generation and Characterization of Tyrosine-Insensitive Mutants

2005 ◽  
Vol 71 (11) ◽  
pp. 7224-7228 ◽  
Author(s):  
Tina Lütke-Eversloh ◽  
Gregory Stephanopoulos
Keyword(s):  
Escherichia Coli ◽  
Dna Sequences ◽  
Molecular Level ◽  
Feedback Inhibition ◽  
Feedback Regulation ◽  
The Other ◽  
Chorismate Mutase ◽  
Amino Acid Substitutions ◽  
Prephenate Dehydrogenase

ABSTRACT In order to get insights into the feedback regulation by tyrosine of the Escherichia coli chorismate mutase/prephenate dehydrogenase (CM/PDH), which is encoded by the tyrA gene, feedback-inhibition-resistant (fbr) mutants were generated by error-prone PCR. The tyrA fbr mutants were selected by virtue of their resistance toward m-fluoro-d,l-tyrosine, and seven representatives were characterized on the biochemical as well as on the molecular level. The PDH activities of the purified His6-tagged TyrA proteins exhibited up to 35% of the enzyme activity of TyrAWT, but tyrosine did not inhibit the mutant PDH activities. On the other hand, CM activities of the TyrAfbr mutants were similar to those of the TyrAWT protein. Analyses of the DNA sequences of the tyrA genes revealed that tyrA 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.

Production of chorismate mutase-prephenate dehydrogenase by a strain of Escherichia coli carrying a multicopy, tyrA plasmid

1982 ◽  
Vol 717 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Suresh B. Bhosale ◽  
Julian I. Rood ◽  
Margaret K. Sneddon ◽  
John F. Morrison
Keyword(s):  
Escherichia Coli ◽  
Chorismate Mutase ◽  
Prephenate Dehydrogenase

Chorismate mutase/prephenate dehydrogenase from Escherichia coli K12: purification, characterization, and identification of a reactive cysteine

Biochemistry ◽  
1984 ◽  
Vol 23 (25) ◽  
pp. 6240-6249 ◽  
Author(s):  
Graham S. Hudson ◽  
Vic Wong ◽  
Barrie E. Davidson
Keyword(s):  
Escherichia Coli ◽  
Chorismate Mutase ◽  
Escherichia Coli K12 ◽  
Prephenate Dehydrogenase

Chorismate mutase-prephenate dehydrogenase from Escherichia coli: positive cooperativity with substrates and inhibitors

Biochemistry ◽  
1985 ◽  
Vol 24 (5) ◽  
pp. 1116-1121 ◽  
Author(s):  
Richard I. Christopherson ◽  
John F. Morrison
Keyword(s):  
Escherichia Coli ◽  
Chorismate Mutase ◽  
Prephenate Dehydrogenase ◽  
Positive Cooperativity

Reversion of the Tyrosine Ochre Strain Escherichia coli WU3610 under Starvation Conditions Depends on a New Gene tas

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1627-1635 ◽  
Author(s):  
Andrew R Timms ◽  
Bryn A Bridges
Keyword(s):  
Escherichia Coli ◽  
Reductase Activity ◽  
Spontaneous Mutation ◽  
Single Copy ◽  
Chorismate Mutase ◽  
Multicopy Plasmid ◽  
Reading Frame ◽  
Prephenate Dehydrogenase ◽  
Slow Growing ◽  
Starvation Conditions

Abstract When 3 × 108 bacteria of the Escherichia coli tyrA14(oc) leu308(am) strain WU3610 are plated on glucose salts agar supplemented with leucine only, colonies of slow-growing Tyr+ suppressor mutants begin to appear after about a week and increase in numbers roughly linearly with time thereafter (stationary phase or starvation-associated mutation). From a library constructed from two of these mutants, a clone was obtained that suppressed the tyrosine requirement of WU3610 when present on a multicopy plasmid. The activity was identified to an open reading frame we call tas, the sequence for which has homology with a variety of known genes with aldo-keto reductase activity. The activity of tas complements the prephenate dehydrogenase dysfunction of tyrA14 (the chorismate mutase activity of tyrA possibly being still functional). A strain deleted for tas showed no spontaneous mutation under starvation conditions. Whereas neither tas+ nor tas bacteria showed any increase in viable or total count when plated under conditions of tyrosine starvation at 3 × 108 cells per plate, at lower density (~107 per plate) tas+ but not tas bacteria showed considerable residual growth. We suggest that the single copy of tas present in WU3610 allows cryptic cell or DNA turnover under conditions of tyrosine starvation and that this is an essential prerequisite for starvation-associated mutation in this system. The target gene for mutation is not tas, although an increase in the expression of this gene, for example, resulting from a suppressor mutation affecting supercoiling, could be responsible for the slow-growing Tyr+ phenotype.

Chorismate mutase-prephenate dehydrogenase from Escherichia coli: spatial relationship of the mutase and dehydrogenase sites

Biochemistry ◽  
1983 ◽  
Vol 22 (7) ◽  
pp. 1650-1656 ◽  
Author(s):  
Richard I. Christopherson ◽  
Elizabeth Heyde ◽  
John F. Morrison
Keyword(s):  
Escherichia Coli ◽  
Spatial Relationship ◽  
Chorismate Mutase ◽  
Prephenate Dehydrogenase ◽  
Relationship Of
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