Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 35.11 kDa 
• Atom Count: 2778 
• Residue Count: 313 
• Unique protein chains: 1

4QUK

Crystal Structure of Cinnamyl-Alcohol Dehydrogenase 2 Mutant K169A

• DOI: 10.2210/pdb4QUK/pdb

• Classification: OXIDOREDUCTASE
• Organism(s): Medicago truncatula
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2014-07-10 Released: 2014-10-01 
• Deposition Author(s): Pan, H., Wang, X.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free: 0.225 
• R-Value Work: 0.185 
• R-Value Observed: 0.185 

Literature

Structural Studies of Cinnamoyl-CoA Reductase and Cinnamyl-Alcohol Dehydrogenase, Key Enzymes of Monolignol Biosynthesis.

Pan, H., Zhou, R., Louie, G.V., Muhlemann, J.K., Bomati, E.K., Bowman, M.E., Dudareva, N., Dixon, R.A., Noel, J.P., Wang, X.

(2014) Plant Cell 26: 3709-3727

• PubMed: 25217505 
• DOI: 10.1105/tpc.114.127399
• Structures With Same Primary Citation


• PubMed Abstract: 
  

The enzymes cinnamoyl-CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) catalyze the two key reduction reactions in the conversion of cinnamic acid derivatives into monolignol building blocks for lignin polymers in plant cell walls. Here, we describe detailed functional and structural analyses of CCRs from Medicago truncatula and Petunia hybrida and of an atypical CAD (CAD2) from M. truncatula. These enzymes are closely related members of the short-chain dehydrogenase/reductase (SDR) superfamily. Our structural studies support a reaction mechanism involving a canonical SDR catalytic triad in both CCR and CAD2 and an important role for an auxiliary cysteine unique to CCR. Site-directed mutants of CAD2 (Phe226Ala and Tyr136Phe) that enlarge the phenolic binding site result in a 4- to 10-fold increase in activity with sinapaldehyde, which in comparison to the smaller coumaraldehyde and coniferaldehyde substrates is disfavored by wild-type CAD2. This finding demonstrates the potential exploitation of rationally engineered forms of CCR and CAD2 for the targeted modification of monolignol composition in transgenic plants. Thermal denaturation measurements and structural comparisons of various liganded and unliganded forms of CCR and CAD2 highlight substantial conformational flexibility of these SDR enzymes, which plays an important role in the establishment of catalytically productive complexes of the enzymes with their NADPH and phenolic substrates.

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Organizational Affiliation: 

Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401 [e-mail].

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Dihydroflavonol-4-reductase	A	319	Medicago truncatula	Mutation(s): 1  Gene Names: MTR_3g005170, 11427940, MtrunA17_Chr3g0077221 EC: 1.1.1 (PDB Primary Data), 1.1.1.195 (UniProt)
Find proteins for G7IYC1 (Medicago truncatula) Go to UniProtKB:  G7IYC1

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free: 0.225 
• R-Value Work: 0.185 
• R-Value Observed: 0.185 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 37.797	α = 90
b = 76.565	β = 90
c = 106.045	γ = 90

Software Package:

Software Name	Purpose
CrystalClear	data collection
CNS	refinement
HKL-2000	data reduction
HKL-2000	data scaling
CNS	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2014-07-10 
• Released Date: 2014-10-01 
Deposition Author(s): Pan, H., Wang, X.

Revision History 

• Version 1.0: 2014-10-01
  Type: Initial release
  
• Version 1.1: 2014-11-12
  Changes: Database references