Crystal structure of XIAP BIR1 domain (P21 form)

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.196 

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This is version 1.4 of the entry. See complete history


Crystal structure of the BIR1 domain of XIAP in two crystal forms

Lin, S.C.Huang, Y.Lo, Y.C.Lu, M.Wu, H.

(2007) J Mol Biol 372: 847-854

  • DOI: https://doi.org/10.1016/j.jmb.2007.07.019
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    X-linked inhibitor of apoptosis (XIAP) is a potent negative regulator of apoptosis. It also plays a role in BMP signaling, TGF-beta signaling, and copper homeostasis. Previous structural studies have shown that the baculoviral IAP repeat (BIR2 and BIR3) domains of XIAP interact with the IAP-binding-motifs (IBM) in several apoptosis proteins such as Smac and caspase-9 via the conserved IBM-binding groove. Here, we report the crystal structure in two crystal forms of the BIR1 domain of XIAP, which does not possess this IBM-binding groove and cannot interact with Smac or caspase-9. Instead, the BIR1 domain forms a conserved dimer through the region corresponding to the IBM-binding groove. Structural and sequence analyses suggest that this dimerization of BIR1 in XIAP may be conserved in other IAP family members such as cIAP1 and cIAP2 and may be important for the action of XIAP in TGF-beta and BMP signaling and the action of cIAP1 and cIAP2 in TNF receptor signaling.

  • Organizational Affiliation

    Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10021, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Baculoviral IAP repeat-containing protein 4A [auth D],
B [auth C],
C [auth B],
D [auth A]
111Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P98170 (Homo sapiens)
Explore P98170 
Go to UniProtKB:  P98170
PHAROS:  P98170
GTEx:  ENSG00000101966 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP98170
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on ZN

Download Ideal Coordinates CCD File 
E [auth D],
G [auth C],
K [auth B],
L [auth A]
Query on EOH

Download Ideal Coordinates CCD File 
F [auth D]
H [auth C]
I [auth C]
J [auth C]
M [auth A]
F [auth D],
H [auth C],
I [auth C],
J [auth C],
M [auth A],
N [auth A]
C2 H6 O
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.196 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 36.563α = 90
b = 72.983β = 95.69
c = 68.904γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
ADSCdata collection

Structure Validation

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Entry History 

Deposition Data

  • Released Date: 2007-09-18 
  • Deposition Author(s): Lin, S.-C.

Revision History  (Full details and data files)

  • Version 1.0: 2007-09-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Refinement description
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description
  • Version 1.4: 2023-11-29
    Changes: Database references