2B48: Bcl-xl 3d Domain Swapped Dimer

Dimeric interactions among anti- and pro-apoptotic members of the BCL-2 protein family are dynamically regulated and intimately involved in survival and death functions. We report the structure of a BCL-X(L) homodimers a 3D-domain swapped dimer (3DDS). The X-ray crystal structure demonstrates the mutual exchange of carboxy-terminal regions including BH2 (Bcl-2 homology 2) between monomer subunits, with the hinge region occurring at the hairpin turn between the fifth and sixth alpha helices. Both BH3 peptide-binding hydrophobic grooves are unoccupied in the 3DDS dimer and available for BH3 peptide binding, as confirmed by sedimentation velocity analysis. BCL-X(L) 3DDS dimers have increased pore-forming activity compared to monomers, suggesting that 3DDS dimers may act as intermediates in membrane pore formation. Chemical crosslinking studies of Cys-substituted BCL-X(L) proteins demonstrate that 3DDS dimers form in synthetic lipid vesicles.
PDB ID: 2B48Download
MMDB ID: 37541
PDB Deposition Date: 2005/9/22
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 3.45  Å
Source Organism:
Similar Structures:
Biological Unit for 2B48: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 2B48
Label Count Molecule
Proteins (2 molecules)
Apoptosis Regulator Bcl-x(Gene symbol: BCL2L1)
Molecule annotation
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Citing MMDB