Structure of transmembrane pore induced by Bax-derived peptide: evidence for lipidic pores.
The structures of transmembrane pores formed by a large family of pore-forming proteins and peptides are unknown. These proteins, whose secondary structures are predominantly alpha-helical segments, and many peptides form pores in membranes without a crystallizable protein assembly, contrary to the family of beta-pore-forming proteins, which form crystallizable beta-barrel pores. Nevertheless, a protein-induced pore in membranes is commonly assumed to be a protein channel. Here, we show a type of peptide-induced pore that is not framed by a peptide structure. Peptide-induced pores in multiple bilayers were long-range correlated into a periodically ordered lattice and analyzed by X-ray diffraction. We found the pores induced by Bax-derived helical peptides were at least partially framed by a lipid monolayer. Evidence suggests that the formation of such lipidic pores is a major mechanism for alpha-pore-forming proteins, including apoptosis-regulator Bax.
Qian
Shuo
S
Department of Physics and Astronomy, Rice University, Houston, TX 77251, USA.
Wang
Wangchen
W
Yang
Lin
L
Huang
Huey W
HW
D021961:Cell Membrane Structures / Q000378:metabolism* / Q000648:ultrastructure*; D008958:Models, Molecular; D010455:Peptides / Q000378:metabolism*; D016062:Porosity; D011487:Protein Conformation; D014961:X-Ray Diffraction; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
D010455:Peptides; D051028:bcl-2-Associated X Protein