4Z11

Latent aurone synthase (polyphenol oxidase) from natural source


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.186 

Starting Model: experimental
View more details

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases.

Molitor, C.Mauracher, S.G.Rompel, A.

(2016) Proc Natl Acad Sci U S A 113: E1806-E1815

  • DOI: https://doi.org/10.1073/pnas.1523575113
  • Primary Citation of Related Structures:  
    4Z0Y, 4Z0Z, 4Z11, 4Z12, 4Z13

  • PubMed Abstract: 

    Tyrosinases and catechol oxidases belong to the family of polyphenol oxidases (PPOs). Tyrosinases catalyze theo-hydroxylation and oxidation of phenolic compounds, whereas catechol oxidases were so far defined to lack the hydroxylation activity and catalyze solely the oxidation of o-diphenolic compounds. Aurone synthase from Coreopsis grandiflora (AUS1) is a specialized plant PPO involved in the anabolic pathway of aurones. We present, to our knowledge, the first crystal structures of a latent plant PPO, its mature active and inactive form, caused by a sulfation of a copper binding histidine. Analysis of the latent proenzyme's interface between the shielding C-terminal domain and the main core provides insights into its activation mechanisms. As AUS1 did not accept common tyrosinase substrates (tyrosine and tyramine), the enzyme is classified as a catechol oxidase. However, AUS1 showed hydroxylase activity toward its natural substrate (isoliquiritigenin), revealing that the hydroxylase activity is not correlated with the acceptance of common tyrosinase substrates. Therefore, we propose that the hydroxylase reaction is a general functionality of PPOs. Molecular dynamics simulations of docked substrate-enzyme complexes were performed, and a key residue was identified that influences the plant PPO's acceptance or rejection of tyramine. Based on the evidenced hydroxylase activity and the interactions of specific residues with the substrates during the molecular dynamics simulations, a novel catalytic reaction mechanism for plant PPOs is proposed. The presented results strongly suggest that the physiological role of plant catechol oxidases were previously underestimated, as they might hydroxylate their--so far unknown--natural substrates in vivo.


  • Organizational Affiliation

    Institut für Biophysikalische Chemie, Fakultät für Chemie, Universität Wien, 1090 Vienna, Austria.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Aurone synthase
A, B, C, D
517Coreopsis grandifloraMutation(s): 0 
UniProt
Find proteins for A0A075DN54 (Coreopsis grandiflora)
Explore A0A075DN54 
Go to UniProtKB:  A0A075DN54
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A075DN54
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.186 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.57α = 90
b = 174.1β = 105.27
c = 102.54γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
PHASERphasing
XSCALEdata scaling

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Austrian Science FundAustriaP25217-N28

Revision History  (Full details and data files)

  • Version 1.0: 2016-03-23
    Type: Initial release
  • Version 1.1: 2016-03-30
    Changes: Database references
  • Version 1.2: 2016-04-13
    Changes: Database references
  • Version 1.3: 2019-02-20
    Changes: Advisory, Data collection, Derived calculations
  • Version 1.4: 2024-01-10
    Changes: Data collection, Database references, Derived calculations, Refinement description