7OFO image
Entry Detail
PDB ID:
7OFO
Keywords:
Title:
NMR structure of the Bak transmembrane helix in lipid nanodiscs
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2021-05-05
Release Date:
2021-06-23
Method Details:
Experimental Method:
Conformers Calculated:
50
Conformers Submitted:
20
Selection Criteria:
structures with the lowest energy
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Bcl-2 homologous antagonist/killer
Chain IDs:A
Chain Length:30
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
High-resolution analysis of the conformational transition of pro-apoptotic Bak at the lipid membrane.
Embo J. 40 e107159 e107159 (2021)
PMID: 34523144 DOI: 10.15252/embj.2020107159

Abstact

Permeabilization of the outer mitochondrial membrane by pore-forming Bcl2 proteins is a crucial step for the induction of apoptosis. Despite a large set of data suggesting global conformational changes within pro-apoptotic Bak during pore formation, high-resolution structural details in a membrane environment remain sparse. Here, we used NMR and HDX-MS (Hydrogen deuterium exchange mass spectrometry) in lipid nanodiscs to gain important high-resolution structural insights into the conformational changes of Bak at the membrane that are dependent on a direct activation by BH3-only proteins. Furthermore, we determined the first high-resolution structure of the Bak transmembrane helix. Upon activation, α-helix 1 in the soluble domain of Bak dissociates from the protein and adopts an unfolded and dynamic potentially membrane-bound state. In line with this finding, comparative protein folding experiments with Bak and anti-apoptotic BclxL suggest that α-helix 1 in Bak is a metastable structural element contributing to its pro-apoptotic features. Consequently, mutagenesis experiments aimed at stabilizing α-helix 1 yielded Bak variants with delayed pore-forming activity. These insights will contribute to a better mechanistic understanding of Bak-mediated membrane permeabilization.

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Primary Citation of related structures