Components::SNARE (protein)


Journal::snare    Membrane::fusion    Title::volume    Pages::proteins    Complex::snap-    Issue::vauthors

Components The core SNARE complex is a 4-<math>\alpha</math>-helix bundle.<ref name="sutton1998"> {{#invoke:Citation/CS1|citation |CitationClass=journal }} </ref> Synaptobrevin and syntaxin contribute one <math>\alpha</math>-helix each, while SNAP-25 participates with two <math>\alpha</math>-helices (abbreviated as Sn1 and Sn2). The interacting amino acid residues that zip the SNARE complex can be grouped into layers. Each layer has 4 amino acid residues - one residue per each of the 4 <math>\alpha</math>-helices. In the center of the complex is the zero ionic layer composed of one arginine (R) and three glutamine (Q) residues, and it is flanked by leucine zippering. Layers '-1', '+1' and '+2' at the centre of the complex most closely follow ideal leucine-zipper geometry and aminoacid composition.<ref name="fass1998">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref>

The zero ionic layer is composed of R56 from VAMP-2, Q226 from syntaxin-1A, Q53 from Sn1 and Q174 from Sn2, and is completely buried within the leucine-zipper layers. The positively charged guanidino group of the arginine (R) residue interact with the carboxyl groups of each of the three glutamine (Q) residues.

The flanking leucine-zipper layers act as a water-tight seal to shield the ionic interactions from the surrounding solvent. Exposure of the zero ionic layer to the water solvent by breaking the flanking leucine zipper leads to instability of the SNARE complex and is the putative mechanism by which <math>\alpha</math>-SNAP and NSF recycle the SNARE complexes after the completion of synaptic vesicle exocytosis.

SNARE (protein) sections
Intro   Types    Structure    Membrane fusion    Components    Mechanism of membrane fusion   Regulatory Effects on Exocytosis   Toxins    Role in neurotransmitter release    Role in autophagy   References  External links