title: Single molecule mechanical probing of the SNARE protein interactions.
abstract: Exocytotic release of neurotransmitters is mediated by the ternary soluble N-ethyl maleimide-sensitive fusion protein attachment protein receptors (SNAREs) complex, comprised of syntaxin (Sx), synaptosome-associated protein of 25 kDa (SNAP25), and synaptobrevin 2 (Sb2). Since exocytosis involves the nonequilibrium process of association and dissociation of bonds between molecules of the SNARE complex, dynamic measurements at the single molecule level are necessary for a detailed understanding of these interactions. To address this issue, we used the atomic force microscope in force spectroscopy mode to show from single molecule investigations of the SNARE complex, that Sx1A and Sb2 are zippered throughout their entire SNARE domains without the involvement of SNAP25. When SNAP25B is present in the complex, it creates a local interaction at the 0 (ionic) layer by cuffing Sx1A and Sb2. Force loading rate studies indicate that the ternary complex interaction is more stable than the Sx1A-Sb2 interaction.
authors.affiliation: Department of Physics, University of California, Riverside, California 92521, USA.
authors.forename: W
authors.initials: W
authors.lastname: Liu
authors.forename: Vedrana
authors.initials: V
authors.lastname: Montana
authors.forename: Jihong
authors.initials: J
authors.lastname: Bai
authors.forename: Edwin R
authors.initials: ER
authors.lastname: Chapman
authors.forename: U
authors.initials: U
authors.lastname: Mohideen
authors.forename: Vladimir
authors.initials: V
authors.lastname: Parpura
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D006639:Histidine / Q000737:chemistry; D006801:Humans; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism*; D050827:Syntaxin 1 / Q000378:metabolism*; D050988:Vesicle-Associated Membrane Protein 2 / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1; D050988:Vesicle-Associated Membrane Protein 2; D006639:Histidine