title: Common intermediates and kinetics, but different energetics, in the assembly of SNARE proteins.
abstract: Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are evolutionarily conserved machines that couple their folding/assembly to membrane fusion. However, it is unclear how these processes are regulated and function. To determine these mechanisms, we characterized the folding energy and kinetics of four representative SNARE complexes at a single-molecule level using high-resolution optical tweezers. We found that all SNARE complexes assemble by the same step-wise zippering mechanism: slow N-terminal domain (NTD) association, a pause in a force-dependent half-zippered intermediate, and fast C-terminal domain (CTD) zippering. The energy release from CTD zippering differs for yeast (13 kBT) and neuronal SNARE complexes (27 kBT), and is concentrated at the C-terminal part of CTD zippering. Thus, SNARE complexes share a conserved zippering pathway and polarized energy release to efficiently drive membrane fusion, but generate different amounts of zippering energy to regulate fusion kinetics.
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Zorman
authors.affiliation: Department of Physics, Yale University, New Haven, United States.
authors.forename: Aleksander A
authors.initials: AA
authors.lastname: Rebane
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: Lu
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: Guangcan
authors.initials: G
authors.lastname: Yang
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Molski
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: Jeff
authors.initials: J
authors.lastname: Coleman
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: Frederic
authors.initials: F
authors.lastname: Pincet
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: James E
authors.initials: JE
authors.lastname: Rothman
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, United States.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004735:Energy Transfer; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D052898:Optical Tweezers; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D050765:Qa-SNARE Proteins / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D050600:SNARE Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013816:Thermodynamics; D050988:Vesicle-Associated Membrane Protein 2 / Q000737:chemistry / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; C498858:Snap23 protein, rat; D050988:Vesicle-Associated Membrane Protein 2; D033921:Vesicular Transport Proteins
keywords: E. coli; SNARE assembly; SNAREs; biophysics; cell biology; energy landscape; membrane fusion; optical tweezers; protein folding; structural biology