2HXC

Crystal structure of the benzylamine complex of aromatic amine dehydrogenase in N-semiquinone form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.172 
  • R-Value Work: 0.147 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Atomic level insight into the oxidative half-reaction of aromatic amine dehydrogenase.

Roujeinikova, A.Scrutton, N.S.Leys, D.

(2006) J Biol Chem 281: 40264-40272

  • DOI: 10.1074/jbc.M605559200
  • Primary Citation of Related Structures:  
    2HXC, 2IUR, 2IUQ, 2IUP, 2IUV

  • PubMed Abstract: 
  • The quinoprotein aromatic amine dehydrogenase (AADH) uses a covalently bound tryptophan tryptophylquinone (TTQ) cofactor to oxidatively deaminate primary aromatic amines. Recent crystal structures have provided insight into the reductive half-reaction. In contrast, no atomic details are available for the oxidative half-reaction ...

    The quinoprotein aromatic amine dehydrogenase (AADH) uses a covalently bound tryptophan tryptophylquinone (TTQ) cofactor to oxidatively deaminate primary aromatic amines. Recent crystal structures have provided insight into the reductive half-reaction. In contrast, no atomic details are available for the oxidative half-reaction. The TTQ O7 hydroxyl group is protonated during reduction, but it is unclear how this proton can be removed during the oxidative half-reaction. Furthermore, compared with the electron transfer from the N-quinol form, electron transfer from the non-physiological O-quinol form to azurin is significantly slower. Here we report crystal structures of the O-quinol, N-quinol, and N-semiquinone forms of AADH. A comparison of oxidized and substrate reduced AADH species reveals changes in the TTQ-containing subunit, extending from residues in the immediate vicinity of the N-quinol to the putative azurin docking site, suggesting a mechanism whereby TTQ redox state influences interprotein electron transfer. In contrast, chemical reduction of the TTQ center has no significant effect on protein conformation. Furthermore, structural reorganization upon substrate reduction places a water molecule near TTQ O7 where it can act as proton acceptor. The structure of the N-semiquinone, however, is essentially similar to oxidized AADH. Surprisingly, in the presence of substrate a covalent N-semiquinone substrate adduct is observed. To our knowledge this is the first detailed insight into a complex, branching mechanism of quinone oxidation where significant structural reorganization upon reduction of the quinone center directly influences formation of the electron transfer complex and nature of the electron transfer process.


    Organizational Affiliation

    Manchester Interdisciplinary Biocentre, University of Manchester, Manchester M1 7DN, United Kingdom.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Aromatic amine dehydrogenase DH135Alcaligenes faecalisMutation(s): 0 
Gene Names: aauA
EC: 1.4.99.4 (PDB Primary Data), 1.4.9.2 (UniProt)
Find proteins for P84887 (Alcaligenes faecalis)
Explore P84887 
Go to UniProtKB:  P84887
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Aromatic amine dehydrogenase AB361Alcaligenes faecalisMutation(s): 0 
Gene Names: aauB
EC: 1.4.99.4 (PDB Primary Data), 1.4.9.2 (UniProt)
Find proteins for P84888 (Alcaligenes faecalis)
Explore P84888 
Go to UniProtKB:  P84888
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ABN
Query on ABN

Download Ideal Coordinates CCD File 
D, H
BENZYLAMINE
C7 H9 N
WGQKYBSKWIADBV-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
TTQ
Query on TTQ
D,HL-PEPTIDE LINKINGC11 H13 N3 O3TRP
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.172 
  • R-Value Work: 0.147 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.792α = 90
b = 88.593β = 90.3
c = 79.989γ = 90
Software Package:
Software NamePurpose
SCALAdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
MOSFLMdata reduction
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-09-26
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance