Related Experiment Video
Updated: Jun 2, 2026

Detergent-free Ultrafast Reconstitution of Membrane Proteins into Lipid Bilayers Using Fusogenic Complementary-charged Proteoliposomes.
Published on: April 5, 2018
Design and characterization of endosomal-pH-responsive coiled coils for constructing an artificial membrane fusion
Ayumi Kashiwada1, Mana Tsuboi, Naohide Takamura
1Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Narashino, Chiba 275-8575, Japan. kashiwada.ayumi@nihon-u.ac.jp
Abstract:
A weakly acidic pH-responsive polypeptide is believed to have the potential for an endosome escape function in a polypeptide-triggered delivery system. For constructing a membrane fusion device with pH-responsiveness, we have designed novel polypeptides that are capable of forming an α2 coiled coil structure. Circular dichroism spectroscopy reveals that a polypeptide, AP-LZ(EH5), with a Glu and His salt-bridge pair at a staggered position in the hydrophobic core forms a stable coiled coil structure only at endosomal pH values (pH 5.0 to 5.5). On the basis of their endosomal-pH responsiveness, a boronic acid/polypeptide conjugate (BA-H5-St) was also designed as a pilot molecule to construct a pH-responsive, one-way membrane fusion system with a sugarlike compound (phosphatidylinositol: PI)-containing liposome as a target. Membrane fusion behavior was characterized by lipid-mixing, inner-leaflet lipid-mixing, and contents-mixing assays. These studies reveal that membrane fusion is clearly observed when the pH of the experimental system is changed from 7.4 (physiological condition) to 5.0 (endosomal condition).
Related Concept Videos
SNAREs and Membrane Fusion
SNAREs exist in pairs that symmetrically interact and catalyze the fusion of the lipid bilayers in vesicle and target organelle. v-SNARE in the vesicle membrane are single polypeptide chains that bind to a complementary t-SNARE, composed of 2...
Fusion of Secretory Vesicles with the Plasma Membrane
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
Mechanisms of Membrane Domain Formation
Another mechanism for membrane domain formation involves membrane proteins interacting with cytoskeletal...
Clathrin Coated Vesicles
Pinching-off of Coated Vesicles
Introduction to Membrane Traffic
The transport of soluble and membrane proteins is mediated by transport vesicles that collect cargo from one cellular compartment and deliver it to another by fusing with the target organelle membrane. The Rab...

