PDBsum entry 2cf5

Oxidoreductase

PDB id: 2cf5

Contents

Protein chain

352 a.a. *

Metals

_ZN ×2

Waters ×199

* Residue conservation analysis

PDB id:

2cf5

Name:

Oxidoreductase

Title:

Crystal structures of the arabidopsis cinnamyl alcohol dehydrogenases, atcad5

Structure:

Cinnamyl alcohol dehydrogenase. Chain: a. Synonym: atccad5, cad. Engineered: yes

Source:

Arabidopsis thaliana. Mouse ear cress. Organism_taxid: 3702. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.00Å R-factor: 0.195 R-free: 0.235

Authors:

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

Key ref:

B.Youn et al. (2006). Crystal structures and catalytic mechanism of the Arabidopsis cinnamyl alcohol dehydrogenases AtCAD5 and AtCAD4. Org Biomol Chem, 4, 1687-1697. PubMed id: 16633561

Date:

16-Feb-06 Release date: 20-Feb-07

Protein chain

O49482  (CADH5_ARATH) -  Cinnamyl alcohol dehydrogenase 5 from Arabidopsis thaliana

Seq: 357 a.a.

Struc: 352 a.a.

Enzyme reactions

• Enzyme class: E.C.1.1.1.195 - cinnamyl-alcohol dehydrogenase.
• Reaction: (E)-cinnamyl alcohol + NADP⁺ = (E)-cinnamaldehyde + NADPH + H⁺

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

Org Biomol Chem 4:1687-1697 (2006)

PubMed id: 16633561

Crystal structures and catalytic mechanism of the Arabidopsis cinnamyl alcohol dehydrogenases AtCAD5 and AtCAD4.

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

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. 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.