2b48 | pdb_00002b48
Bcl-XL 3D Domain Swapped Dimer
Structural highlights
Function[B2CL1_HUMAN] Potent inhibitor of cell death. Inhibits activation of caspases (By similarity). Appears to regulate cell death by blocking the voltage-dependent anion channel (VDAC) by binding to it and preventing the release of the caspase activator, CYC1, from the mitochondrial membrane. Also acts as a regulator of G2 checkpoint and progression to cytokinesis during mitosis.[1] [2] Isoform Bcl-X(S) promotes apoptosis.[3] [4] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDimeric 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. BCL-XL dimerization by three-dimensional domain swapping.,O'Neill JW, Manion MK, Maguire B, Hockenbery DM J Mol Biol. 2006 Feb 17;356(2):367-81. Epub 2005 Dec 1. PMID:16368107[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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