8FIO

Hypothetical anthocyanidin reductase from Sorghum bicolor-NADP(H) and naringenin complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.97 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 

Starting Model: experimental
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Literature

Structural Similarities and Overlapping Activities among Dihydroflavonol 4-Reductase, Flavanone 4-Reductase, and Anthocyanidin Reductase Offer Metabolic Flexibility in the Flavonoid Pathway.

Lewis, J.A.Zhang, B.Harza, R.Palmer, N.Sarath, G.Sattler, S.E.Twigg, P.Vermerris, W.Kang, C.

(2023) Int J Mol Sci 24

  • DOI: https://doi.org/10.3390/ijms241813901
  • Primary Citation of Related Structures:  
    8FEM, 8FEN, 8FET, 8FEU, 8FEV, 8FEW, 8FIO, 8FIP

  • PubMed Abstract: 

    Flavonoids are potent antioxidants that play a role in defense against pathogens, UV-radiation, and the detoxification of reactive oxygen species. Dihydroflavonol 4-reductase (DFR) and flavanone 4-reductase (FNR) reduce dihydroflavonols and flavanones, respectively, using NAD(P)H to produce flavan-(3)-4-(di)ols in flavonoid biosynthesis. Anthocyanidin reductase (ANR) reduces anthocyanidins to flavan-3-ols. In addition to their sequences, the 3D structures of recombinant DFR, FNR and ANR from sorghum and switchgrass showed a high level of similarity. The catalytic mechanism, substrate-specificity and key residues of three reductases were deduced from crystal structures, site-directed mutagenesis, molecular docking, kinetics, and thermodynamic ana-lyses. Although DFR displayed its highest activity against dihydroflavonols, it also showed activity against flavanones and anthocyanidins. It was inhibited by the flavonol quercetin and high concentrations of dihydroflavonols/flavonones. SbFNR1 and SbFNR2 did not show any activity against dihydroflavonols. However, SbFNR1 displayed activity against flavanones and ANR activity against two anthocyanidins, cyanidin and pelargonidin. Therefore, SbFNR1 and SbFNR2 could be specific ANR isozymes without delphinidin activity. Sorghum has high concentrations of 3-deoxyanthocyanidins in vivo, supporting the observed high activity of SbDFR against flavonols. Mining of expression data indicated substantial induction of these three reductase genes in both switchgrass and sorghum in response to biotic stress. Key signature sequences for proper DFR/ANR classification are proposed and could form the basis for future metabolic engineering of flavonoid metabolism.


  • Organizational Affiliation

    Department of Chemistry, Washington State University, Pullman, WA 99164, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Epimerase domain-containing protein
A, B
345Sorghum bicolorMutation(s): 0 
Gene Names: SORBI_3006G226700
UniProt
Find proteins for A0A1B6PND3 (Sorghum bicolor)
Explore A0A1B6PND3 
Go to UniProtKB:  A0A1B6PND3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A1B6PND3
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.97 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.089α = 90
b = 112.787β = 90
c = 122.808γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XDSdata scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Science Foundation (NSF, United States)United StatesCHE-1804699
National Science Foundation (NSF, United States)United StatesMCB-2043248

Revision History  (Full details and data files)

  • Version 1.0: 2023-09-20
    Type: Initial release
  • Version 1.1: 2023-10-11
    Changes: Database references