Information on EC 5.4.3.11 - phenylalanine aminomutase (D-beta-phenylalanine forming)

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The expected taxonomic range for this enzyme is: Bacteria, Eukaryota

EC NUMBER
COMMENTARY hide
5.4.3.11
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RECOMMENDED NAME
GeneOntology No.
phenylalanine aminomutase (D-beta-phenylalanine forming)
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
L-phenylalanine = D-beta-phenylalanine
show the reaction diagram
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-
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SYSTEMATIC NAME
IUBMB Comments
L-phenylalanine 2,3-aminomutase [(S)-3-amino-3-phenylpropanoate]
The enzyme from the bacterium Pantoea agglomerans produces D-beta-phenylalanine, an intermediate in the biosynthesis of the polyketide non-ribosomal antibiotic andrimid. The enzyme contains the cofactor 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO), which is formed autocatalytically by cyclization and dehydration of the three amino-acid residues alanine, serine and glycine. cf. EC 5.4.3.10, phenylalanine aminomutase (L-beta-phenylalanine forming).
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
putative
UniProt
Manually annotated by BRENDA team
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
2'-methyl-(2S)-alpha-phenylalanine
2'-methyl-beta-phenylalanine
show the reaction diagram
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plus about 2% of 2'-methyl-(E)-cinnamate
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?
D-beta-phenylalanine
L-phenylalanine
show the reaction diagram
L-phenylalanine
D-beta-phenylalanine
show the reaction diagram
L-phenylalanine
L-beta-phenylalanine
show the reaction diagram
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when L-Phe enters the active site, the carboxylate group forms a bidentate salt bridge with residue R325. The carboxylate group further interacts with residue Q319. The amine group and the pro-3S hydrogen atom are oriented in an anti-periplanar geometry suitable for the elimination step. A nucleophilic attack of the amine group of the substrate on the 4-methylideneimidazole-5-one cofactor group preceeds abstraction of the proton by the general base Y80, possibly assisted by another basic group, and elimination of 4-methylideneimidazole-5-one-NH2. This leads to formation of trans-cinnamic acid, with the carboxylate group still bound to residue R325. The next step is the readdition of 4-methylideneimidazole-5-one-NH2 to the beta-position and of the proton to the alpha-position. This step requires exposure of the Re face of Cbeta to the 4-methylideneimidazole-5-one-NH2 and the carboxylate group to function as a good electron sink
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r
additional information
?
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ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
4-methylidene-1H-imidazol-5(4H)-one
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cofactor is formed autocatalytically from a Thr-Ser-Gly tandem
4-methylideneimidazole-5-one
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.027 - 0.04
D-beta-phenylalanine
0.022 - 0.05
L-phenylalanine
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.059 - 0.22
D-beta-phenylalanine
0.061 - 0.159
L-phenylalanine
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2.2 - 5.53
D-beta-phenylalanine
12227
1.2 - 7.19
L-phenylalanine
104
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
45
aminomutase activity
50
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aminomutase activity
additional information
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
to 1.7 A resolution with cinnamate included in the crystallization buffer. The monomer consists of mostly alphahelices that run parallel to one another and form a four-helix bundle at the center. The catalytically relevant species is a dimer of dimers, in which the two monomers in the asymmetric unit are related by a crystallographic twofold axis to the other two monomers that comprise the catalytically functional tetramer, and each subunit contains an active site. During the reaction, the phenylpropanoid carbon backbone remains mostly stationary above the amino group that is attached to the cofactor moiety
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TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
60
3 h, no loss of activity
65
3 h, 60% residual activity
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
F455A
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reaction proceeds at approximately 2% of the rate of wild-type, in a 40:60 ratio of products D-beta-phenylalanine and trans-cinnamate, where trans-cinnamate prevails
F455N
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reaction proceeds at approximately 2% of the rate of wild-type, in a 40:60 ratio of products D-beta-phenylalanine and trans-cinnamate, where trans-cinnamate prevails