4PXD

The crystal structure of EcAAH in complex with allantoate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.168 
  • R-Value Observed: 0.171 

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This is version 1.2 of the entry. See complete history


Literature

Structural insights into the substrate specificity of (s)-ureidoglycolate amidohydrolase and its comparison with allantoate amidohydrolase.

Shin, I.Han, K.Rhee, S.

(2014) J Mol Biol 426: 3028-3040

  • DOI: https://doi.org/10.1016/j.jmb.2014.06.017
  • Primary Citation of Related Structures:  
    4PXB, 4PXC, 4PXD, 4PXE

  • PubMed Abstract: 

    In plants, the ureide pathway is a metabolic route that converts the ring nitrogen atoms of purine into ammonia via sequential enzymatic reactions, playing an important role in nitrogen recovery. In the final step of the pathway, (S)-ureidoglycolate amidohydrolase (UAH) catalyzes the conversion of (S)-ureidoglycolate into glyoxylate and releases two molecules of ammonia as by-products. UAH is homologous in structure and sequence with allantoate amidohydrolase (AAH), an upstream enzyme in the pathway with a similar function as that of an amidase but with a different substrate. Both enzymes exhibit strict substrate specificity and catalyze reactions in a concerted manner, resulting in purine degradation. Here, we report three crystal structures of Arabidopsis thaliana UAH (bound with substrate, reaction intermediate, and product) and a structure of Escherichia coli AAH complexed with allantoate. Structural analyses of UAH revealed a distinct binding mode for each ligand in a bimetal reaction center with the active site in a closed conformation. The ligand directly participates in the coordination shell of two metal ions and is stabilized by the surrounding residues. In contrast, AAH, which exhibits a substrate-binding site similar to that of UAH, requires a larger active site due to the additional ureido group in allantoate. Structural analyses and mutagenesis revealed that both enzymes undergo an open-to-closed conformational transition in response to ligand binding and that the active-site size and the interaction environment in UAH and AAH are determinants of the substrate specificities of these two structurally homologous enzymes.


  • Organizational Affiliation

    Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Allantoate amidohydrolase
A, B
413Escherichia coli K-12Mutation(s): 1 
Gene Names: allCglxB7ylbBb0516JW0504
EC: 3.5.3
UniProt
Find proteins for P77425 (Escherichia coli (strain K12))
Explore P77425 
Go to UniProtKB:  P77425
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP77425
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.168 
  • R-Value Observed: 0.171 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.829α = 90
b = 171.864β = 90
c = 43.244γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-07-23
    Type: Initial release
  • Version 1.1: 2022-08-24
    Changes: Database references, Derived calculations
  • Version 1.2: 2023-11-08
    Changes: Data collection, Refinement description