4qve
Crystal structure of Bcl-xL in complex with BID BH3 domain
Structural highlights
FunctionB2CL1_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] Publication Abstract from PubMedApoptosis or programmed cell death is a regulatory process in cells in response to stimuli perturbing physiological conditions. The Bcl-2 family of proteins plays an important role in regulating homeostasis during apoptosis. In the process, the molecular interactions among the three members of this family, the pro-apoptotic, anti-apoptotic and BH3-only proteins at the mitochondrial outer membrane define the fate of a cell. Here, we report the crystal structures of the human anti-apoptotic protein Bcl-XL in complex with BH3-only BIDBH3 and BIMBH3 peptides determined at 2.0 A and 1.5 A resolution, respectively. The BH3 peptides bind to the canonical hydrophobic pocket in Bcl-XL and adopt an alpha helical conformation in the bound form. Despite a similar structural fold, a comparison with other BH3 complexes revealed structural differences due to their sequence variations. In the Bcl-XL -BIDBH3 complex we observed a large pocket, in comparison with other BH3 complexes, lined by residues from helices alpha1, alpha2, alpha3, and alpha5 located adjacent to the canonical hydrophobic pocket. These results suggest that there are differences in the mode of interactions by the BH3 peptides that may translate into functional differences in apoptotic regulation. Proteins 2015. (c) 2015 Wiley Periodicals, Inc. Bh3 induced conformational changes in Bcl-X revealed by crystal structure and comparative analysis.,Rajan S, Choi M, Baek K, Yoon HS Proteins. 2015 Apr 23. doi: 10.1002/prot.24816. PMID:25907960[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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