2CF6

Crystal Structures of the Arabidopsis Cinnamyl Alcohol Dehydrogenases AtCAD5


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.201 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Crystal Structures and Catalytic Mechanisms of the Arabidopsis Cinnamyl Alcohol Dehydrogenases Atcad5 and Atcad4

Youn, B.Camacho, R.Moinuddin, S.G.Lee, C.Davin, L.B.Lewis, N.G.Kang, C.

(2006) Org Biomol Chem 4: 1687

  • DOI: 10.1039/b601672c
  • Primary Citation of Related Structures:  
    2CF5, 2CF6

  • PubMed Abstract: 
  • The cinnamyl alcohol dehydrogenase (CAD) multigene family in planta encodes proteins catalyzing the reductions of various phenylpropenyl aldehyde derivatives in a substrate versatile manner, and whose metabolic products are the precursors of structural lignins, health-related lignans, and various other metabolites ...

    The cinnamyl alcohol dehydrogenase (CAD) multigene family in planta encodes proteins catalyzing the reductions of various phenylpropenyl aldehyde derivatives in a substrate versatile manner, and whose metabolic products are the precursors of structural lignins, health-related lignans, and various other metabolites. In Arabidopsis thaliana, the two isoforms, AtCAD5 and AtCAD4, are the catalytically most active being viewed as mainly involved in the formation of guaiacyl/syringyl lignins. In this study, we determined the crystal structures of AtCAD5 in the apo-form and as a binary complex with NADP+, respectively, and modeled that of AtCAD4. Both AtCAD5 and AtCAD4 are dimers with two zinc ions per subunit and belong to the Zn-dependent medium chain dehydrogenase/reductase (MDR) superfamily, on the basis of their overall 2-domain structures and distribution of secondary structural elements. The catalytic Zn2+ ions in both enzymes are tetrahedrally coordinated, but differ from those in horse liver alcohol dehydrogenase since the carboxyl side-chain of Glu70 is ligated to Zn2+ instead of water. Using AtCAD5, site-directed mutagenesis of Glu70 to alanine resulted in loss of catalytic activity, thereby indicating that perturbation of the Zn2+ coordination was sufficient to abolish catalytic activity. The substrate-binding pockets of both AtCAD5 and AtCAD4 were also examined, and found to be significantly different and smaller compared to that of a putative aspen sinapyl alcohol dehydrogenase (SAD) and a putative yeast CAD. While the physiological roles of the aspen SAD and the yeast CAD are uncertain, they nevertheless have a high similarity in the overall 3D structures to AtCAD5 and 4. With the bona fide CAD's from various species, nine out of the twelve residues which constitute the proposed substrate-binding pocket were, however, conserved. This is provisionally considered as indicative of a characteristic fingerprint for the CAD family.


    Organizational Affiliation

    School of Molecular Biosciences, Washington State University, Pullman, 99164-4660, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CINNAMYL ALCOHOL DEHYDROGENASEA357Arabidopsis thalianaMutation(s): 0 
Gene Names: CAD5CAD-DCAD6LCAD-DAt4g34230F28A23.10
EC: 1.1.1.195
UniProt
Find proteins for O49482 (Arabidopsis thaliana)
Explore O49482 
Go to UniProtKB:  O49482
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO49482
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAP
Query on NAP

Download Ideal Coordinates CCD File 
D [auth A]NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE
C21 H28 N7 O17 P3
XJLXINKUBYWONI-NNYOXOHSSA-N
 Ligand Interaction
ZN
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A],
C [auth A]
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.201 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.71α = 90
b = 54.71β = 90
c = 303.93γ = 90
Software Package:
Software NamePurpose
X-PLORrefinement
AMoREphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-02-20
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance