5ktg
Crystal structure of mouse Bak BH3-in-groove homodimer (GFP)
Structural highlights
FunctionGFP_AEQVI Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin.BAK_MOUSE In the presence of an appropriate stimulus, accelerates programmed cell death by binding to, and antagonizing the anti-apoptotic action of BCL2 (By similarity). Publication Abstract from PubMedIn mitochondrial apoptosis, Bak is activated by death signals to form pores of unknown structure on the mitochondrial outer membrane via homooligomerization. Cytochrome c and other apoptotic factors are released from the intermembrane space through these pores, initiating downstream apoptosis events. Using chemical crosslinking and double electron electron resonance (DEER)-derived distance measurements between specific structural elements in Bak, here we clarify how the Bak pore is assembled. We propose that previously described BH3-in-groove homodimers (BGH) are juxtaposed via the 'alpha3/alpha5' interface, in which the C-termini of helices alpha3 and alpha5 are in close proximity between two neighboring Bak homodimers. This interface is observed concomitantly with the well-known 'alpha6:alpha6' interface. We also mapped the contacts between Bak homodimers and the lipid bilayer based on EPR spectroscopy topology studies. Our results suggest a model for the lipidic Bak pore, whereby the mitochondrial targeting C-terminal helix does not change topology to accommodate the lining of the pore lumen by BGH. Assembly of Bak homodimers into higher order homooligomers in the mitochondrial apoptotic pore.,Mandal T, Shin S, Aluvila S, Chen HC, Grieve C, Choe JY, Cheng EH, Hustedt EJ, Oh KJ Sci Rep. 2016 Aug 4;6:30763. doi: 10.1038/srep30763. PMID:27488021[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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