3P7J

Drosophila HP1a chromo shadow domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.201 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

The HP1a Disordered C Terminus and Chromo Shadow Domain Cooperate to Select Target Peptide Partners.

Mendez, D.L.Kim, D.Chruszcz, M.Stephens, G.E.Minor, W.Khorasanizadeh, S.Elgin, S.C.

(2011) Chembiochem 12: 1084-1096

  • DOI: 10.1002/cbic.201000598
  • Primary Citation of Related Structures:  
    3P7J

  • PubMed Abstract: 
  • Drosophila melanogaster heterochromatin protein 1a (HP1a) is essential for compacted heterochromatin structure and the associated gene silencing. Its chromo shadow domain (CSD) is well known for binding to peptides that contain a PXVXL motif. Heterochromatin protein 2 (HP2) is a non-histone chromosomal protein that associates with HP1a in the pericentric heterochromatin, telomeres, and the fourth chromosome ...

    Drosophila melanogaster heterochromatin protein 1a (HP1a) is essential for compacted heterochromatin structure and the associated gene silencing. Its chromo shadow domain (CSD) is well known for binding to peptides that contain a PXVXL motif. Heterochromatin protein 2 (HP2) is a non-histone chromosomal protein that associates with HP1a in the pericentric heterochromatin, telomeres, and the fourth chromosome. Using NMR spectroscopy, fluorescence polarization, and site-directed mutagenesis, we identified an LCVKI motif in HP2 that binds to the HP1a CSD. The binding affinity of the HP2 fragment is approximately two orders of magnitude higher than that of peptides from PIWI (with a PRVKV motif), AF10 (with a PLVVL motif), or CG15356 (with LYPLL and LSIVA motifs). To delineate differential interactions of the HP1a CSD, we characterized its structure, backbone dynamics, and dimerization constant. We found that the dimerization constant is bracketed by the affinities of HP2 and PIWI, which dock to the same HP1a homodimer surface. This suggests that HP2, but not PIWI, interaction can drive the homodimerization of HP1a. Interestingly, the integrity of the disordered C-terminal extension (CTE) of HP1a is essential for discriminatory binding, whereas swapping the PXVXL motifs does not confer specificity. Serine phosphorylation at the peptide binding surface of the CSD is thought to regulate heterochromatin assembly. Glutamic acid substitution at these sites destabilizes HP1a dimers, but improves the interaction with both binding partners. Our studies underscore the importance of CSD dimerization and cooperation with the CTE in forming distinct complexes of HP1a.


    Organizational Affiliation

    Department of Biology, Washington University, St. Louis, MO 63130, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Heterochromatin protein 1A, B87Drosophila melanogasterMutation(s): 0 
Gene Names: Su(var)205HP1CG8409
UniProt
Find proteins for P05205 (Drosophila melanogaster)
Explore P05205 
Go to UniProtKB:  P05205
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download Ideal Coordinates CCD File 
C [auth B]GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.201 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 44.755α = 90
b = 56.545β = 90
c = 67.295γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
PHENIXrefinement
CNSrefinement
REFMACrefinement
Cootmodel building
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-02-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance