1YWT

Crystal structure of the human sigma isoform of 14-3-3 in complex with a mode-1 phosphopeptide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.233 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

A structural basis for 14-3-3sigma functional specificity.

Wilker, E.W.Grant, R.A.Artim, S.C.Yaffe, M.B.

(2005) J.Biol.Chem. 280: 18891-18898

  • DOI: 10.1074/jbc.M500982200

  • PubMed Abstract: 
  • The 14-3-3 family of proteins includes seven isotypes in mammalian cells that play numerous diverse roles in intracellular signaling. Most 14-3-3 proteins form homodimers and mixed heterodimers between different isotypes, with overlapping roles in li ...

    The 14-3-3 family of proteins includes seven isotypes in mammalian cells that play numerous diverse roles in intracellular signaling. Most 14-3-3 proteins form homodimers and mixed heterodimers between different isotypes, with overlapping roles in ligand binding. In contrast, one mammalian isoform, 14-3-3sigma, expressed primarily in epithelial cells, appears to play a unique role in the cellular response to DNA damage and in human oncogenesis. The biological and structural basis for these 14-3-3sigma-specific functions is unknown. We demonstrate that endogenous 14-3-3sigma preferentially forms homodimers in cells. We have solved the x-ray crystal structure of 14-3-3sigma bound to an optimal phosphopeptide ligand at 2.4 angstroms resolution. The structure reveals the presence of stabilizing ring-ring and salt bridge interactions unique to the 14-3-3sigma homodimer structure and potentially destabilizing electrostatic interactions between subunits in 14-3-3sigma-containing heterodimers, rationalizing preferential homodimerization of 14-3-3sigma in vivo. The interaction of the phosphopeptide with 14-3-3 reveals a conserved mechanism for phospho-dependent ligand binding, implying that the phosphopeptide binding cleft is not the critical determinant of the unique biological properties of 14-3-3sigma. Instead, the structure suggests a second ligand binding site involved in 14-3-3sigma-specific ligand discrimination. We have confirmed this by site-directed mutagenesis of three sigma-specific residues that uniquely define this site. Mutation of these residues to the alternative sequence that is absolutely conserved in all other 14-3-3 isotypes confers upon 14-3-3sigma the ability to bind to Cdc25C, a ligand that is known to bind to other 14-3-3 proteins but not to sigma.


    Organizational Affiliation

    Center for Cancer Research, Department of Biology and Division of Biological Engineering, Massachsuetts Institute of Technology, Cambridge, Massachusetts 02139, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
14-3-3 protein sigma
A, B
248Homo sapiensMutation(s): 0 
Gene Names: SFN (HME1)
Find proteins for P31947 (Homo sapiens)
Go to Gene View: SFN
Go to UniProtKB:  P31947
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
synthetic optimal phosphopeptide (mode-1)
C, D
12N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
SEP
Query on SEP
C, D
L-PEPTIDE LINKINGC3 H8 N O6 PSER
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.233 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 56.173α = 90.00
b = 137.093β = 90.00
c = 155.313γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
HKL-2000data reduction
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-03-01
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance