The neuronal t-SNARE complex is a parallel four-helix bundle.
Assembly of the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) complex is an essential step for neurotransmitter release in synapses. The presynaptic plasma membrane associated proteins (t-SNAREs), SNAP-25 (synaptosome-associated protein of 25,000 Da) and syntaxin 1A may form an intermediate complex that later binds to vesicle-associated membrane protein 2 (VAMP2). Using spin labeling electron paramagnetic resonance (EPR), we found that the two t-SNARE proteins assemble into a parallel four-helix bundle that consists of two identical syntaxin 1A components and the N-terminal and C-terminal domains of SNAP-25. Although the structure is generally similar to that of the final SNARE complex, the middle region of the helical bundle appears more flexible in the t-SNARE complex. Such flexibility might facilitate interactions between VAMP2 and the t-SNARE complex.
Department of Chemistry, University of California, Berkeley, California 94720, USA.
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Xiao
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Poirier
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Bennett
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Shin
D004578:Electron Spin Resonance Spectroscopy; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism; D009474:Neurons / Q000737:chemistry*; D018583:Pliability; D017433:Protein Structure, Secondary; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D013113:Spin Labels; D050825:Synaptosomal-Associated Protein 25; D013696:Temperature; D033921:Vesicular Transport Proteins
D046911:Macromolecular Substances; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D013113:Spin Labels; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins