Membrane fusion mediated by peptidic SNARE protein analogues: Evaluation of FRET-based bulk leaflet mixing assays.

Peptide-mediated membrane fusion is frequently studied with in vitro bulk leaflet mixing assays based on Förster resonance energy transfer (FRET). In these, customized liposomes with fusogenic peptides are equipped with lipids which are labeled with fluorophores that form a FRET pair. Since FRET is dependent on distance and membrane fusion comes along with lipid mixing, the assays allow for conclusions on the membrane fusion process.

Synthesis of PNA-Peptide Conjugates as Functional SNARE Protein Mimetics.

PNA-peptide conjugates are versatile tools in chemical biology, which are employed in a variety of applications. Here, we present the synthesis of PNA-peptide conjugates that serve as SNARE protein-mimicking biooligomers. They resemble the structure of native SNARE proteins but exhibit a much simpler architecture.

PNA Hybrid Sequences as Recognition Units in SNARE-Protein-Mimicking Peptides.

Membrane fusion is an essential process in nature and is often accomplished by the specific interaction of SNARE proteins. SNARE model systems, in which SNARE domains are replaced by small artificial units, represent valuable tools to study membrane fusion in vitro. The synthesis and analysis is presented of SNARE model peptides that exhibit a recognition motif composed of two different types of peptide nucleic acid (PNA) sequences.

Role of the transmembrane domain in SNARE protein mediated membrane fusion: peptide nucleic acid/peptide model systems.

Fusion of synaptic vesicles with the presynaptic plasma membrane is mediated by Soluble NSF (N-ethylmaleimide-sensitive factor) Attachment Protein Receptor proteins also known as SNAREs. The backbone of this essential process is the assembly of SNAREs from opposite membranes into tight four helix bundles forcing membranes in close proximity. With model systems resembling SNAREs with reduced complexity we aim to understand how these proteins work at the molecular level.

Membrane protein sequestering by ionic protein-lipid interactions.

Neuronal exocytosis is catalysed by the SNAP receptor protein syntaxin-1A, which is clustered in the plasma membrane at sites where synaptic vesicles undergo exocytosis. However, how syntaxin-1A is sequestered is unknown. Here we show that syntaxin clustering is mediated by electrostatic interactions with the strongly anionic lipid phosphatidylinositol-4,5-bisphosphate (PIP2).