3LJA

Using Soft X-Rays for a Detailed Picture of Divalent Metal Binding in the Nucleosome

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.75 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.223 

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This is version 1.2 of the entry. See complete history. 

Literature

Using soft X-rays for a detailed picture of divalent metal binding in the nucleosome

Wu, B., Davey, C.A.

(2010) J.Mol.Biol. 398: 633-640

  • DOI: 10.1016/j.jmb.2010.03.038

  • PubMed Abstract: 

    • Divalent metals associate with DNA in a site-selective manner, which can influence nucleosome positioning, mobility, compaction, and recognition by nuclear factors. We previously characterized divalent metal binding in the nucleosome core using hard ...

    Divalent metals associate with DNA in a site-selective manner, which can influence nucleosome positioning, mobility, compaction, and recognition by nuclear factors. We previously characterized divalent metal binding in the nucleosome core using hard (short-wavelength) X-rays allowing high-resolution crystallographic determination of the strongest affinity sites, which revealed that Mn(2+) associates with the DNA major groove in a sequence- and conformation-dependent manner. In this study, we obtained diffraction data with soft X-rays at the Mn(2+) absorption edge for a core particle crystal in the presence of 10 mM MnSO(4), mimicking prevailing Mg(2+) concentration in the nucleus. This provides an exceptional view of counterion binding in the nucleosome through identification of 45 divalent metal binding sites. In addition to that at the well-characterized major interparticle interface, only one other histone-divalent metal binding site is found, which corresponds to a symmetry-related counterpart on the 'free' H2B alpha1 helix C-terminus. This emphasizes the importance of the alpha-helix dipole in ion binding and suggests that the H2B motif may serve as a nucleation site in nucleosome compaction. The 43 sites associated with the DNA are characterized by (1) high-affinity direct coordination at the most electrostatically favorable major groove locations, (2) metal hydrate binding to the major groove, (3) direct coordination to phosphate groups at sites of high charge density, (4) metal hydrate binding in the minor groove, or (5) metal hydrate-divalent anion pairing. Metal hydrates are found within the minor groove only at locations displaying a narrow range of high-intermediate width and to which histone N-terminal tails are not associated or proximal. This indicates that divalent metals and histone tails can both collaborate and compete in minor groove association, which sheds light on nucleosome solubility and chromatin compaction behavior.

    Organizational Affiliation: 

    Division of Structural and Computational Biology, School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Histone H3.2
A, E
135Xenopus laevisMutation(s): 0 
Find proteins for P84233 (Xenopus laevis)
Go to UniProtKB:  P84233
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Histone H4
B, F
102Xenopus laevisMutation(s): 0 
Find proteins for P62799 (Xenopus laevis)
Go to UniProtKB:  P62799
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Histone H2A
C, G
129Xenopus laevisMutation(s): 0 
Find proteins for P06897 (Xenopus laevis)
Go to UniProtKB:  P06897
Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
Histone H2B 1.1
D, H
122Xenopus laevisMutation(s): 0 
Find proteins for P02281 (Xenopus laevis)
Go to UniProtKB:  P02281
Entity ID: 5
MoleculeChainsLengthOrganism
147mer DNAI147N/A
Entity ID: 6
MoleculeChainsLengthOrganism
147mer DNAJ147N/A
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN
Download SDF File 
Download CCD File 
E, H, I, J
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4
Download SDF File 
Download CCD File 
D, G, H
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.75 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.223 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 106.348α = 90.00
b = 109.785β = 90.00
c = 182.424γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
MOSFLMdata reduction
MAR345dtbdata collection
AMoREphasing
REFMACrefinement

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 2010-01-26 
  • Released Date: 2010-04-14 
  • Deposition Author(s): Wu, B., Davey, C.A.

Revision History 

  • Version 1.0: 2010-04-14
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2014-02-12
    Type: Database references