title: Complexin splits the membrane-proximal region of a single SNAREpin.
abstract: Complexin (Cpx) is thought to be a major regulator of soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE)-dependent membrane fusion. Although the inhibition of membrane fusion by Cpx has been frequently reported, its structural basis has been elusive and an anticipated disruption of the SNARE core has never been observed. In the present study, to mimic the natural environment, we assembled a single SNAREpin between two nanodisc membrane patches. Single-molecule FRET (smFRET) detects a large conformational change, specifically at the C-terminal half, whereas no conformational change is observed at the N-terminal half. Our results suggest that Cpx splits the C-terminal half of the SNARE core at least 10 Å (1 Å=0.1 nm), whereby inhibiting further progression of SNARE zippering and membrane fusion.
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, U.S.A.
authors.forename: Linxiang
authors.initials: L
authors.lastname: Yin
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, U.S.A.
authors.forename: Jaewook
authors.initials: J
authors.lastname: Kim
authors.affiliation: Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, U.S.A. colishin@iastate.edu.
authors.forename: Yeon-Kyun
authors.initials: YK
authors.lastname: Shin
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D050600:SNARE Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D009419:Nerve Tissue Proteins; D050600:SNARE Proteins
keywords: complexin; fluorescence/Förster resonance energy transfer (FRET); nanodisc; single molecule; soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE)