6CNP

Crystal structure of MBD2 complex with methylated CpG island


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.191 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural basis for the ability of MBD domains to bind methyl-CG and TG sites in DNA.

Liu, K.Xu, C.Lei, M.Yang, A.Loppnau, P.Hughes, T.R.Min, J.

(2018) J Biol Chem 293: 7344-7354

  • DOI: 10.1074/jbc.RA118.001785
  • Primary Citation of Related Structures:  
    6CNQ, 6CNP, 6C1A, 6C1U, 6C1T, 6C1V

  • PubMed Abstract: 
  • Cytosine methylation is a well-characterized epigenetic mark and occurs at both CG and non-CG sites in DNA. Both methylated CG (mCG)- and mCH (H = A, C, or T)-containing DNAs, especially mCAC-containing DNAs, are recognized by methyl-CpG-binding protein 2 (MeCP2) to regulate gene expression in neuron development ...

    Cytosine methylation is a well-characterized epigenetic mark and occurs at both CG and non-CG sites in DNA. Both methylated CG (mCG)- and mCH (H = A, C, or T)-containing DNAs, especially mCAC-containing DNAs, are recognized by methyl-CpG-binding protein 2 (MeCP2) to regulate gene expression in neuron development. However, the molecular mechanism involved in the binding of methyl-CpG-binding domain (MBD) of MeCP2 to these different DNA motifs is unclear. Here, we systematically characterized the DNA-binding selectivities of the MBD domains in MeCP2 and MBD1-4 with isothermal titration calorimetry-based binding assays, mutagenesis studies, and X-ray crystallography. We found that the MBD domains of MeCP2 and MBD1-4 bind mCG-containing DNAs independently of the sequence identity outside the mCG dinucleotide. Moreover, some MBD domains bound to both methylated and unmethylated CA dinucleotide-containing DNAs, with a preference for the CAC sequence motif. We also found that the MBD domains bind to mCA or nonmethylated CA DNA by recognizing the complementary TG dinucleotide, which is consistent with an overlooked ligand of MeCP2, i.e. the matrix/scaffold attachment regions (MARs/SARs) with a consensus sequence of 5'-GGTGT-3' that was identified in early 1990s. Our results also explain why MeCP2 exhibits similar binding affinity to both mCA- and hmCA-containing dsDNAs. In summary, our results suggest that in addition to mCG sites, unmethylated CA or TG sites also serve as DNA-binding sites for MeCP2 and other MBD-containing proteins. This discovery expands the genome-wide activity of MBD-containing proteins in gene regulation.


    Organizational Affiliation

    the Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.



Macromolecules

Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Methyl-CpG-binding domain protein 2A, B96Homo sapiensMutation(s): 0 
Gene Names: MBD2
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UBB5 (Homo sapiens)
Explore Q9UBB5 
Go to UniProtKB:  Q9UBB5
PHAROS:  Q9UBB5
Protein Feature View
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  • Reference Sequence
  • Find similar nucleic acids by:  Sequence   |   Structure
  • Entity ID: 2
    MoleculeChainsLengthOrganismImage
    DNA (5'-D(*GP*CP*CP*AP*CP*(5CM)P*GP*GP*TP*GP*GP*C)-3')C, D, E, F12synthetic construct
    Protein Feature View
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    • Reference Sequence
    Experimental Data & Validation

    Experimental Data

    • Method: X-RAY DIFFRACTION
    • Resolution: 2.10 Å
    • R-Value Free: 0.218 
    • R-Value Work: 0.189 
    • R-Value Observed: 0.191 
    • Space Group: P 1
    Unit Cell:
    Length ( Å )Angle ( ˚ )
    a = 40.96α = 101.57
    b = 41.32β = 99.46
    c = 58.67γ = 100.54
    Software Package:
    Software NamePurpose
    Aimlessdata scaling
    PHENIXrefinement
    PDB_EXTRACTdata extraction
    XDSdata reduction
    PHASERphasing

    Structure Validation

    View Full Validation Report



    Entry History 

    Deposition Data

    Revision History  (Full details and data files)

    • Version 1.0: 2018-03-28
      Type: Initial release
    • Version 1.1: 2018-04-18
      Changes: Data collection, Database references
    • Version 1.2: 2018-05-23
      Changes: Data collection, Database references