Search results for "Intermembrane space"
showing 3 items of 3 documents
Structure Of Complexes Of Helix-5 From Bax With Lipid Membranes
2009
Bax is a proapoptotic protein implicated in the release of cell-death activating factors from the mitochondrial intermembrane space. Although the structure of the membrane-bound forms of Bax is unknown, it has been proposed to form proteolipidic pores. Studies with synthetic lipid vesicles have shown that fragments encompassing helix-5 of Bax retain a membrane permeabilization ability that is similar to that of the full-length protein. Here we report on the structure of peptide-membrane complexes formed by a Bax helix-5 peptide and lipid bilayers. The relative orientation of the peptide and the lipids are determined using site-specific infrared spectroscopy, assisted by isotopic labeling of…
Peptides corresponding to helices 5 and 6 of Bax can independently form large lipid pores
2006
Proteins of the B-cell lymphoma protein 2 (Bcl2) family are key regulators of the apoptotic cascade, controlling the release of apoptotic factors from the mitochondrial intermembrane space. A helical hairpin found in the core of water-soluble folds of these proteins has been reported to be the pore- forming domain. Here we show that peptides including any of the two a-helix fragments of the hairpin of Bcl2 associated protein X (Bax) can independently induce release of large labelled dextrans from synthetic lipid vesicles. The permeability promoted by these peptides is influenced by intrinsic monolayer curvature and accompanied by fast transbilayer redis- tribution of lipids, supporting a to…
Chloroplast signal length requirement reflects the outer membrane and TOC complex dimension
2015
Background and Purpose: The evolution of an efficient preprotein targeting and translocation system was a central prerequisite for the endosymbiotic integration of a -proteobacteria and cyanobacteria as cellular organelles. Today, it is widely accepted that during evolution most (pre-)proteins destined for these two organelles were equipped with an N-terminal targeting signal for localization. While multiple modes of evolution of these extensions are currently discussed, all evolved signals serve the same function – forming a signal for targeting to the correct organelle and translocation across both membranes. We aimed to generalize the current idea for the length requirement of the N-term…