1PK3

Scm SAM domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.215 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural organization of a Sex-comb-on-midleg/polyhomeotic copolymer.

Kim, C.A.Sawaya, M.R.Cascio, D.Kim, W.Bowie, J.U.

(2005) J.Biol.Chem. 280: 27769-27775

  • DOI: 10.1074/jbc.M503055200
  • Primary Citation of Related Structures:  1PK1

  • PubMed Abstract: 
  • The polycomb group proteins are required for the stable maintenance of gene repression patterns established during development. They function as part of large multiprotein complexes created via a multitude of protein-protein interaction domains. Here ...

    The polycomb group proteins are required for the stable maintenance of gene repression patterns established during development. They function as part of large multiprotein complexes created via a multitude of protein-protein interaction domains. Here we examine the interaction between the SAM domains of the polycomb group proteins polyhomeotic (Ph) and Sex-comb-on-midleg (Scm). Previously we showed that Ph-SAM polymerizes as a helical structure. We find that Scm-SAM also polymerizes, and a crystal structure reveals an architecture similar to the Ph-SAM polymer. These results suggest that Ph-SAM and Scm-SAM form a copolymer. Binding affinity measurements between Scm-SAM and Ph-SAM subunits in different orientations indicate a preference for the formation of a single junction copolymer. To provide a model of the copolymer, we determined the structure of the Ph-SAM/Scm-SAM junction. Similar binding modes are observed in both homo- and heterocomplex formation with minimal change in helix axis direction at the polymer joint. The copolymer model suggests that polymeric Scm complexes could extend beyond the local domains of polymeric Ph complexes on chromatin, possibly playing a role in long range repression.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Sex comb on midleg CG9495-PA
A, B, C
89Drosophila melanogasterGene Names: Scm
Find proteins for Q9VHA0 (Drosophila melanogaster)
Go to UniProtKB:  Q9VHA0
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
BME
Query on BME

Download SDF File 
Download CCD File 
A, B, C
BETA-MERCAPTOETHANOL
C2 H6 O S
DGVVWUTYPXICAM-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.215 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 52.150α = 90.00
b = 63.993β = 90.00
c = 103.638γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
CNSrefinement
DENZOdata reduction
EPMRphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-02-15
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance