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
- Primary Citation of Related Structures:  
4TX5 - 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 ...