PNA Hybrid Sequences as Recognition Units in SNARE‐Protein‐Mimicking Peptides

• Published in: Angewandte Chemie International Edition Vol. 57; no. 45; pp. 14932 - 14936
• Main Authors: Hubrich, Barbara E., Kumar, Pawan, Neitz, Hermann, Grunwald, Matthias, Grothe, Tobias, Walla, Peter Jomo, Jahn, Reinhard, Diederichsen, Ulf
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 05-11-2018
• Edition: International ed. in English
• Subjects: Amino acids; Domains; Fusion protein; Glycine; Kinetics; Lipids; liposomes; Membrane fusion; Membrane proteins; Mimicry; model systems; Oligomers; Peptide nucleic acids; Peptides; Proteins; Recognition; SNAP receptors; SNARE proteins; Topology; model systems; liposomes; SNARE proteins; membrane fusion; peptide nucleic acids
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201805752

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. This novel recognition unit is designed to mimic the SNARE zippering mechanism that initiates SNARE‐mediated fusion. It contains N‐(2‐aminoethyl)glycine‐PNA (aeg‐PNA) and alanyl‐PNA, which both recognize the respective complementary strand but differ in duplex topology and duplex formation kinetics. The duplex formation of PNA hybrid oligomers as well as the fusogenicity of the model peptides in lipid‐mixing assays were characterized and the peptides were found to induce liposome fusion. As an unexpected discovery, peptides with a recognition unit containing only five aeg‐PNA nucleo amino acids were sufficient and most efficient to induce liposome fusion.
To set a SNARE: SNARE model peptides with novel peptide nucleic acid (PNA) hybrid sequences as recognition units were synthesized and analyzed. They were made from two topologically different PNAs with the aim of mimicking SNARE zippering. Lipid‐mixing assays revealed that peptides with a pentameric N‐(2‐aminoethyl)glycine (aeg)‐PNA sequence are the most efficient in liposome fusion.