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Catalytic Site Atlas Version 2.2.12
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CSA entry for 1aw8
Original Entry
Title:
Decarboxylase
Compound:
L-aspartate-alpha-decarboxylase
Mutant:
No
UniProt/Swiss-Prot:
P31664-PAND_ECOLI
EC Class:
4.1.1.11
Other CSA Entries:
Overview of all sites for 1aw8
Homologues of 1aw8
Entries for UniProt/Swiss-Prot: P31664
Entries for EC: 4.1.1.11
Other Databases:
PDB entry: 1aw8
PDBsum entry: 1aw8
UniProt/Swiss-Prot: P31664
IntEnz entry: 4.1.1.11
Literature Report:
Introduction:
This enzyme catalyses the formation of beta-alanine from L-aspartate. This is a step in the biosynthetic pathway of pantothenate, the precursor to phosphopantothenate, the acyl carrier found in coenzyme A and acyl carrier proteins. The enzyme requires a main chain rearrangement of the pro-protein to active enzyme. Autocatalytic post-translational modification which cleaves the Gly24-Ser25 peptide bond and converts Ser25 to a pyruvoyl group yield the active enzyme.
Mechanism:
The mechanism involves formation of an imine between the amino group of aspartate and an integral pyruvoyl group. The pyruvol group is formed by an autocatalytic post-translational modification which cleaves the Gly24-Ser25 bond and converts Ser25 into the pyruvoyl group.

Aspartate firstly forms an imine-linkage to the pyruvoyl group of the enzyme, followed by the decarboxylation of the aspartate, forming the extended enolate intermediate. The enolate is then reprotonated by Tyr58 to form an imine intermediate of the product, beta-alanine, which is finally released by hydrolysis to regenerate the pyruvoyl group. Lys9 may play a role in keeping the alpha-carboxyl group of the substrate deprotonated by forming an ion pair.
Sites:

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Found by:
Literature reference 

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
LYSA 9 0Sidechain
ElectrostaticSubstrate
It keeps the alpha-carboxyl group of aspartate deprotonated by forming an ion pair.
Evidence from paper Evidence concerns Evidence type
PubMed ID 15184017 Current protein Conservation of residue
PubMed ID 15184017 Current protein Residue is positioned appropriately (ligand position known)

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
PYRB 25 0
ModifiedModified
It forms an imine linkage to aspartate to initiate the decarboxylation to yield beta-alanine after the reprotonation.
Evidence from paper Evidence concerns Evidence type
PubMed ID 15184017 Current protein Residue is covalently bound to intermediate, based on structural data

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
TYRB 58 0Sidechain
Acid/baseSubstrate
It protonates the enolate intermediate to form an imine intermediate of the product beta-alanine.
Evidence from paper Evidence concerns Evidence type
Evidence from paper listed as having "No PubMed ID available." below. Current protein Chemical modification of residue
PubMed ID 15184017 Current protein Conservation of residue
References:
1
Identification of Tyr58 as the proton donor in the aspartate-alpha-decarboxylase reaction
S. A. Saldanha and L. M. Birch and M. E. Webb and B. K. Nabbs and F. von Delft and A. G. Smith and C. Abell
Chem Commun , 1760-1761 (2001).
No PubMed ID available
2
Crystal structure of the schiff base intermediate prior to decarboxylation in the catalytic cycle of aspartate alpha-decarboxylase.
B. I. Lee and S. W. Suh
J Mol Biol 340, (1) 1-7, (2004).
15184017
3
Identification of Tyr58 as the proton donor in the aspartate-a -decarboxylase reaction
S. A. Saldanha and L. M. Birch and M. E. Webb and B. K. Nabbs and F. von Delft and A. G. Smith and A. Chris
Chem. Commun. 2001, (18) 1760-1761
No PubMed ID available
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