1G73

CRYSTAL STRUCTURE OF SMAC BOUND TO XIAP-BIR3 DOMAIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.227 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis of IAP recognition by Smac/DIABLO.

Wu, G.Chai, J.Suber, T.L.Wu, J.W.Du, C.Wang, X.Shi, Y.

(2000) Nature 408: 1008-1012

  • DOI: 10.1038/35050012

  • PubMed Abstract: 
  • Apoptosis is an essential process in the development and homeostasis of all metazoans. The inhibitor-of-apoptosis (IAP) proteins suppress cell death by inhibiting the activity of caspases; this inhibition is performed by the zinc-binding BIR domains ...

    Apoptosis is an essential process in the development and homeostasis of all metazoans. The inhibitor-of-apoptosis (IAP) proteins suppress cell death by inhibiting the activity of caspases; this inhibition is performed by the zinc-binding BIR domains of the IAP proteins. The mitochondrial protein Smac/DIABLO promotes apoptosis by eliminating the inhibitory effect of IAPs through physical interactions. Amino-terminal sequences in Smac/DIABLO are required for this function, as mutation of the very first amino acid leads to loss of interaction with IAPs and concomitant loss of Smac/DIABLO function. Here we report the high-resolution crystal structure of Smac/DIABLO complexed with the third BIR domain (BIR3) of XIAP. Our results show that the N-terminal four residues (Ala-Val-Pro-Ile) in Smac/DIABLO recognize a surface groove on BIR3, with the first residue Ala binding a hydrophobic pocket and making five hydrogen bonds to neighbouring residues on BIR3. These observations provide a structural explanation for the roles of the Smac N terminus as well as the conserved N-terminal sequences in the Drosophila proteins Hid/Grim/Reaper. In conjunction with other observations, our results reveal how Smac may relieve IAP inhibition of caspase-9 activity. In addition to explaining a number of biological observations, our structural analysis identifies potential targets for drug screening.


    Organizational Affiliation

    Department of Molecular Biology, Princeton University, New Jersey 08544, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SECOND MITOCHONDRIA-DERIVED ACTIVATOR OF CASPASES
A, B
162Homo sapiensGene Names: DIABLO (SMAC)
Find proteins for Q9NR28 (Homo sapiens)
Go to Gene View: DIABLO
Go to UniProtKB:  Q9NR28
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
INHIBITORS OF APOPTOSIS-LIKE PROTEIN ILP
C, D
121Homo sapiensGene Names: XIAP (API3, BIRC4, IAP3)
EC: 6.3.2.-
Find proteins for P98170 (Homo sapiens)
Go to Gene View: XIAP
Go to UniProtKB:  P98170
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
B, D
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.227 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 48.100α = 100.00
b = 52.900β = 104.10
c = 67.100γ = 94.00
Software Package:
Software NamePurpose
MLPHAREphasing
DENZOdata reduction
X-PLORrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-01-10
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance