3D9U

The BIR3 domain of cIAP1 in complex with the N terminal peptide from SMAC/DIABLO (AVPIAQ).

Summary for 3D9U

• Entry DOI: 10.2210/pdb3d9u/pdb
• Related: 3D9T
• Descriptor: Baculoviral IAP repeat-containing protein 2, SMAC/DIABLO, ZINC ION, ... (4 entities in total)
• Functional Keywords: zinc finger, apoptosis, cytoplasm, metal-binding, polymorphism, zinc, zinc-finger
• Biological source: Homo sapiens (human); More
• Cellular location: Cytoplasm: Q13490
• Total number of polymer chains: 2
• Total formula weight: 11837.71

Authors

Kulathila, R.,Price, A. (deposition date: 2008-05-27, release date: 2008-06-10, Last modification date: 2023-08-30)

Primary citation

Kulathila, R.,Vash, B.,Sage, D.,Cornell-Kennon, S.,Wright, K.,Koehn, J.,Stams, T.,Clark, K.,Price, A.
The structure of the BIR3 domain of cIAP1 in complex with the N-terminal peptides of SMAC and caspase-9.
Acta Crystallogr.,Sect.D, 65:58-66, 2009

PubMed Abstract: The inhibitor of apoptosis protein (IAP) family of molecules inhibit apoptosis through the suppression of caspase activity. It is known that the XIAP protein regulates both caspase-3 and caspase-9 through direct protein-protein interactions. Specifically, the BIR3 domain of XIAP binds to caspase-9 via a ;hotspot' interaction in which the N-terminal residues of caspase-9 bind in a shallow groove on the surface of XIAP. This interaction is regulated via SMAC, the N-terminus of which binds in the same groove, thus displacing caspase-9. The mechanism of suppression of apoptosis by cIAP1 is less clear. The structure of the BIR3 domain of cIAP1 (cIAP1-BIR3) in complex with N-terminal peptides from both SMAC and caspase-9 has been determined. The binding constants of these peptides to cIAP1-BIR3 have also been determined using the surface plasmon resonance technique. The structures show that the peptides interact with cIAP1 in the same way that they interact with XIAP: both peptides bind in a similar shallow groove in the BIR3 surface, anchored at the N-terminus by a charge-stabilized hydrogen bond. The binding data show that the SMAC and caspase-9 peptides bind with comparable affinities (85 and 48 nM, respectively).

PubMed: 19153467
DOI: 10.1107/S0907444908039243

Experimental method

X-RAY DIFFRACTION (2.3 Å)