Crystal structure of the Smad3-Smad5 MH1 domain chimera bound to the GGCGC site

Experimental Data Snapshot

  • Resolution: 2.33 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.210 
  • R-Value Observed: 0.212 

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Unveiling the dimer/monomer propensities of Smad MH1-DNA complexes.

Ruiz, L.Kaczmarska, Z.Gomes, T.Aragon, E.Torner, C.Freier, R.Baginski, B.Martin-Malpartida, P.de Martin Garrido, N.Marquez, J.A.Cordeiro, T.N.Pluta, R.Macias, M.J.

(2021) Comput Struct Biotechnol J 19: 632-646

  • DOI: https://doi.org/10.1016/j.csbj.2020.12.044
  • Primary Citation of Related Structures:  
    6TBZ, 6TCE, 6ZMN

  • PubMed Abstract: 

    Smad transcription factors are the main downstream effectors of the Transforming growth factor β superfamily (TGFβ) signalling network. The DNA complexes determined here by X-ray crystallography for the Bone Morphogenetic Proteins (BMP) activated Smad5 and Smad8 proteins reveal that all MH1 domains bind [GGC(GC)|(CG)] motifs similarly, although TGFβ-activated Smad2/3 and Smad4 MH1 domains bind as monomers whereas Smad1/5/8 form helix-swapped dimers. Dimers and monomers are also present in solution, as revealed by NMR. To decipher the characteristics that defined these dimers, we designed chimeric MH1 domains and characterized them using X-ray crystallography. We found that swapping the loop1 between TGFβ- and BMP- activated MH1 domains switches the dimer/monomer propensities. When we scanned the distribution of Smad-bound motifs in ChIP-Seq peaks (Chromatin immunoprecipitation followed by high-throughput sequencing) in Smad-responsive genes, we observed specific site clustering and spacing depending on whether the peaks correspond to BMP- or TGFβ-responsive genes. We also identified significant correlations between site distribution and monomer or dimer propensities. We propose that the MH1 monomer or dimer propensity of Smads contributes to the distinct motif selection genome-wide and together with the MH2 domain association, help define the composition of R-Smad/Smad4 trimeric complexes.

  • Organizational Affiliation

    Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, Barcelona 08028, Spain.


Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Mothers against decapentaplegic homolog 3
A, B
125Homo sapiensMutation(s): 0 
Gene Names: SMAD3MADH3
UniProt & NIH Common Fund Data Resources
Find proteins for P84022 (Homo sapiens)
Explore P84022 
Go to UniProtKB:  P84022
GTEx:  ENSG00000166949 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP84022
Sequence Annotations
  • Reference Sequence

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Entity ID: 2
MoleculeChains LengthOrganismImage
C, D
16Homo sapiens
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.33 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.210 
  • R-Value Observed: 0.212 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.502α = 90
b = 73.416β = 90
c = 111.154γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
autoPROCdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Spanish Ministry of Economy and CompetitivenessSpainBFU2014-53787-P
European CommissionEuropean Union754510

Revision History  (Full details and data files)

  • Version 1.0: 2020-08-26
    Type: Initial release
  • Version 1.1: 2020-10-21
    Changes: Derived calculations
  • Version 1.2: 2021-02-10
    Changes: Database references
  • Version 1.3: 2024-01-31
    Changes: Data collection, Database references, Refinement description