4.2.99.21: isochorismate lyase
This is an abbreviated version!
For detailed information about isochorismate lyase, go to the full flat file.
Word Map on EC 4.2.99.21
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4.2.99.21
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siderophore
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pericyclic
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chorismate-utilizing
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prephenate
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2,3-dihydroxybenzoate
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anthranilate
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mg2+-dependent
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enterobactin
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drug development
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agriculture
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biotechnology
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synthesis
- 4.2.99.21
-
siderophore
-
pericyclic
-
chorismate-utilizing
- prephenate
- 2,3-dihydroxybenzoate
- anthranilate
-
mg2+-dependent
- enterobactin
- drug development
- agriculture
- biotechnology
- synthesis
Reaction
Synonyms
pyochelin biosynthetic protein PchB, IPL, Irp9, isochorismate pyruvate lyase, isochorismate-pyruvate lyase, MbtI, PchA, PchB, PRXR1, salicylate biosynthesis protein pchB, salicylate synthase
ECTree
4.2.99.21 isochorismate lyaseAdvanced search results
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results (Engineering
Engineering on EC 4.2.99.21 - isochorismate lyase
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PROTEIN VARIANTS 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
K147Q
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mutation in proposed catalytic base, about 50fold decrease in activity
A375T
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loss of the physiological isochorismate synthase catalytic efficiency by three orders of magnitude, and a 2fold gain in isochorismate-pyruvate lyase catalytic efficiency
A37I
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mutation increases the rate constant for the chorismate mutase activity by a factor of 1000, and also increases the isochorismate pyruvate lyase catalytic efficiency, by a factor of 6
A43P
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about 25% decrease in both chorismate mutase and isochorismate pyruvate lyase activity
C7A
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mutant has a reduced catalytic free energy of activation of up to 0.17 kcal/mol
C7A/K42C
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mutant has a reduced catalytic free energy of activation of up to 4.2 kcal/mol. Treatment with bromoethylamine leads to 64% recovery of activity
D310E
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physiological isochorismate synthase catalytic efficiency similar to wild-type, 3fold gain in isochorismate-pyruvate lyase catalytic efficiency
D310E/A375T
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similar activity in the isochorismate synthase and isochorismate-pyruvate lyase assays as the A375T variant
I87T
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structure demonstrates considerable mobility, decrease in both chorismate mutase and isochorismate pyruvate lyase activity
I88T
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no isochorismate pyruvate lyase activity, retains chorismate mutase activity
K42A
K42C
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mutant has a reduced catalytic free energy of activation of up to 4.4 kcal/mol. Treatment with bromoethylamine leads to 55% recovery of activity
K42E
K42H
Q91N
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20fold decrease in both isochorismate pyruvate lyase and chorismate mutase activity
R54K
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100fold decrease in both isochorismate pyruvate lyase and chorismate mutase activity
D310E/A375T
more than additive effect of the two individual variants with isochorismate-pyruvate lyase catalytic efficiency three orders of magnitude less than wild-type and undetectable salicylate synthase activity
E281D
salicylate synthase catalytic efficiency is 32fold less than that of the wildtype enzyme. Isochorismate-pyruvate lyase catalytic efficiency loss of 5fold relative to the wildtype
T348A
reduction in salicylate synthase catalytic efficiency by five orders of magnitude. Isochorismate-pyruvate lyase catalytic efficiency is reduced by 17fold
D310E/A375T
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more than additive effect of the two individual variants with isochorismate-pyruvate lyase catalytic efficiency three orders of magnitude less than wild-type and undetectable salicylate synthase activity
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E281D
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salicylate synthase catalytic efficiency is 32fold less than that of the wildtype enzyme. Isochorismate-pyruvate lyase catalytic efficiency loss of 5fold relative to the wildtype
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T348A
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reduction in salicylate synthase catalytic efficiency by five orders of magnitude. Isochorismate-pyruvate lyase catalytic efficiency is reduced by 17fold
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additional information
K42A
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residue presumably involved in electrostatic transition state stabilization. Active site architecture is maintained in mutant K42A
K42A
similar to wild-type, active across the entire pH-range from 4 to 9, with a constant level of activity at pH 5 and above
K42A
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mutation leads to the recovery in catalytic free energy of activation of 2.52.7 kcal/mol compared to mutant K42C. Exogenous addition of ethylamine to the K42A variant leads to a neglible recovery of activity, whereas addition of propylamine causes an additional modest loss in catalytic power
K42E
site-directed mutagenesis of the catalytic residue, inactive mutant, crystal structure determination and comparison to the wild-type structure
K42H
the enzyme develops a pH dependence corresponding to a loss of catalytic power upon deprotonation of the histidine. With loss of the positive charge on the K42H side chain at high pH, the enzyme retains lyase activity at about 100fold lowered catalytic efficiency but loses detectable chorismate mutase activity
K42H
site-directed mutagenesis of the catalytic residue, the mutant enzyme shows 100fold lowered isochorismate lyase catalytic efficiency compared to the wild-type, but loses detectable mutase activity. It develops a pH-dependence corresponding to a loss of catalytic power upon deprotonation of the histidine. The change is not due to changes in active site architecture, but due to the difference in charge at this key site
additional information
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development of an Escherichia coli salicylate (SA) biosensor to screen for IPL activity based on the SalR regulator/psalA promoter combination from Acinetobacter sp. ADP1, to control the expression of the reporter luxCDABE. The sensing components, including the SA-inducible promoter PsalA, the reporter operon luxCDABE and the salR gene encoding the LysR-type regulator of salA, are subcloned from Acinetobacter ADPWH_lux into a plasmid vector. The biosensor is responsive to micromolar concentrations of exogenous SA, and to endogenous SA produced after transformation with a plasmid permitting IPTG-inducible expression of bacterial IPL in this biosensor strain. After screening a cDNA library constructed from turnip crinkle virus (TCV)-infected Arabidopsis thaliana ecotype Di-17, an enzyme, PRXR1, is identified as a putative IPL that converts isochorismate into SA
additional information
Arabidopsis thaliana ecotype Di-17
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development of an Escherichia coli salicylate (SA) biosensor to screen for IPL activity based on the SalR regulator/psalA promoter combination from Acinetobacter sp. ADP1, to control the expression of the reporter luxCDABE. The sensing components, including the SA-inducible promoter PsalA, the reporter operon luxCDABE and the salR gene encoding the LysR-type regulator of salA, are subcloned from Acinetobacter ADPWH_lux into a plasmid vector. The biosensor is responsive to micromolar concentrations of exogenous SA, and to endogenous SA produced after transformation with a plasmid permitting IPTG-inducible expression of bacterial IPL in this biosensor strain. After screening a cDNA library constructed from turnip crinkle virus (TCV)-infected Arabidopsis thaliana ecotype Di-17, an enzyme, PRXR1, is identified as a putative IPL that converts isochorismate into SA
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additional information
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a CM-deficient Escherichia coli mutant, which is auxotrophic for phenylalanine and tyrosine, is functionally complemented by the cloned pchB gene for growth in minimal medium
additional information
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enzyme is not able to complement Escherichia coli entC for the production of enterobactin. Expression of Irp9 in Escherichia coli entC mutant leads to salicylate synthesis
