Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

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Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 44661.72 
• Atom Count: 2893 
• Residue Count: 384 
• Unique protein chains: 1

4TX5

Crystal structure of Smac-DIABLO (in space group P65)

• DOI: 10.2210/pdb4TX5/pdb

• Classification: APOPTOSIS
• Organism(s): Homo sapiens
• Expression System: Escherichia coli


• Deposited: 2014-07-02 Released: 2015-07-15 
• Deposition Author(s): Milani, M., Mastangelo, E., Cossu, F.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.8 Å
• R-Value Free: 0.202 
• R-Value Work: 0.169 

Literature

The activator of apoptosis Smac-DIABLO acts as a tetramer in solution.

Mastrangelo, E., Vachette, P., Cossu, F., Malvezzi, F., Bolognesi, M., Milani, M.

(2015) Biophys.J. 108: 714-723

• PubMed: 25650938 
• DOI: 10.1016/j.bpj.2014.11.3471


• PubMed Abstract: 
  

Smac-DIABLO in its mature form (20.8 kDa) binds to baculoviral IAP repeat (BIR) domains of inhibitor of apoptosis proteins (IAPs) releasing their inhibitory effects on caspases, thus promoting cell death. Despite its apparent molecular mass (∼100 kDa), Smac-DIABLO was held to be a dimer in solution, simultaneously targeting two distinct BIR domains. We report an extensive biophysical characterization of the protein alone and in complex with the X-linked IAP (XIAP)-BIR2-BIR3 domains. Our data show that Smac-DIABLO adopts a tetrameric assembly in solution and that the tetramer is able to bind two BIR2-BIR3 pairs of domains. Our small-angle x-ray scattering-based tetrameric model of Smac-DIABLO/BIR2-BIR3 highlights some conformational freedom of the complex that may be related to optimization of IAPs binding.

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Organizational Affiliation: 

Dipartimento di Bioscienze, Università di Milano, Milano, Italy; CNR-IBF, Istituto di Biofisica, Milano, Italy.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Diablo homolog, mitochondrial	A, B	192	Homo sapiens	Mutation(s): 0  Gene Names: DIABLO (SMAC)
Find proteins for Q9NR28 (Homo sapiens) Go to Gene View: DIABLO Go to UniProtKB:  Q9NR28

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
ACT	A, B	ACETATE ION C2 H3 O2 QTBSBXVTEAMEQO-UHFFFAOYSA-M
MPD	A, B	(4S)-2-METHYL-2,4-PENTANEDIOL C6 H14 O2 SVTBMSDMJJWYQN-YFKPBYRVSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.8 Å
• R-Value Free: 0.202 
• R-Value Work: 0.169 
• Space Group: P 6₅

Unit Cell:

Length (Å)	Angle (°)
a = 90.999	α = 90.00
b = 90.999	β = 90.00
c = 113.802	γ = 120.00

Software Package:

Software Name	Purpose
MOLREP	phasing
iMOSFLM	data reduction
SCALA	data scaling
REFMAC	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2014-07-02 
• Released Date: 2015-07-15 
• Deposition Author(s): Milani, M., Mastangelo, E., Cossu, F.

Revision History 

• Version 1.0: 2015-07-15
  Type: Initial release