title: Role of the transmembrane domain in SNARE protein mediated membrane fusion: peptide nucleic acid/peptide model systems.
abstract: 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. Here, peptide nucleic acids (PNAs) are used as excellent candidates for mimicking the SNARE recognition motif by forming well-characterized duplex structures. Hybridization between complementary PNA strands anchored in liposomes through native transmembrane domains (TMDs) induces the merger of the outer leaflets of the participating vesicles but not of the inner leaflets. A series of PNA/peptide hybrids differing in the length of TMDs and charges at the C-terminal end is presented. Interestingly, mixing of both outer and inner leaflets is seen for TMDs containing an amide in place of the natural carboxylic acid at the C-terminal end. Charged side chains at the C-terminal end of the TMDs are shown to have a negative impact on the mixing of liposomes. The length of the TMDs is vital for fusion as with the use of shortened TMDs, fusion was completely prevented.
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany. udieder@gwdg.de.
authors.forename: Jan-Dirk
authors.initials: JD
authors.lastname: Wehland
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany. udieder@gwdg.de.
authors.forename: Antonina S
authors.initials: AS
authors.lastname: Lygina
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany. udieder@gwdg.de.
authors.forename: Pawan
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany. udieder@gwdg.de.
authors.forename: Samit
authors.initials: S
authors.lastname: Guha
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany. udieder@gwdg.de.
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Hubrich
authors.affiliation: Department of Neurobiology, Max-Planck-Institute of Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Jahn
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany. udieder@gwdg.de.
authors.forename: Ulf
authors.initials: U
authors.lastname: Diederichsen
mesh_terms: D000596:Amino Acids; D008055:Lipids / Q000737:chemistry; D008561:Membrane Fusion; D008954:Models, Biological; D020135:Peptide Nucleic Acids / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D050600:SNARE Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D008055:Lipids; D020135:Peptide Nucleic Acids; D010455:Peptides; D050600:SNARE Proteins