9U6A | pdb_00009u6a

Tubulin-DARPin D1 in complex with a flavone


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 
    0.224 (Depositor), 0.223 (DCC) 
  • R-Value Work: 
    0.183 (Depositor), 0.183 (DCC) 
  • R-Value Observed: 
    0.184 (Depositor) 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

Structure of quercetin 3,4'-dimethyl ether in complex with tubulin provides a rationale for drug design.

Su, Y.Yan, W.Yang, J.Yang, F.

(2025) Biochem Biophys Res Commun 777: 152245-152245

  • DOI: https://doi.org/10.1016/j.bbrc.2025.152245
  • Primary Citation of Related Structures:  
    9U6A

  • PubMed Abstract: 

    Microtubules, composed of αβ-tubulin heterodimers, serve as key targets for anticancer therapeutics due to their critical role in cell division. Numerous compounds have been discovered to interact with tubulin and disrupt microtubule dynamics, particularly those targeting the colchicine-binding domain. Certain flavones, for instance, have demonstrated the ability to bind to this site and suppress microtubule polymerization. Despite their potential, progress in developing flavone-based drugs has been limited by insufficient structural data on tubulin-ligand complexes. Here, we present the high-resolution (1.92 Å) crystal structure of tubulin in complex with a flavone derivative, quercetin 3,4'-dimethyl ether (QU34), elucidating the specific molecular interactions at atomic detail. By analyzing this structure alongside other colchicine-site inhibitors, we clarify prior structure-activity relationship (SAR) findings and offer a framework for designing optimized flavone analogs targeting this site.


  • Organizational Affiliation
    • College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, China.

Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Tubulin alpha-1B chain451Sus scrofaMutation(s): 0 
EC: 3.6.5
UniProt
Find proteins for Q2XVP4 (Sus scrofa)
Explore Q2XVP4 
Go to UniProtKB:  Q2XVP4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ2XVP4
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Tubulin beta chain431Sus scrofaMutation(s): 0 
UniProt
Find proteins for P02554 (Sus scrofa)
Explore P02554 
Go to UniProtKB:  P02554
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02554
Sequence Annotations
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Designed Ankyrin Repeat Protein (DARPIN) D1C [auth F]169synthetic constructMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free:  0.224 (Depositor), 0.223 (DCC) 
  • R-Value Work:  0.183 (Depositor), 0.183 (DCC) 
  • R-Value Observed: 0.184 (Depositor) 
Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 73.6α = 90
b = 91.08β = 97.28
c = 83.17γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-3000data reduction
HKL-3000data scaling
HKL-3000phasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Natural Science Foundation of China (NSFC)China--

Revision History  (Full details and data files)

  • Version 1.0: 2025-04-16
    Type: Initial release
  • Version 1.1: 2025-09-10
    Changes: Database references