Protein Domain : v-SNARE, coiled-coil homology domain IPR042855

Type	Domain
Description	The process of vesicular membrane fusion in eukaryotic cells depends on a conserved fusion machinery called SNARE (soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptors). In the process of vesicle docking, proteins present on the vesicle (v-SNARE) have to bind to their counterpart on the target membrane (t-SNARE) to form a core complex that can then recruit the soluble proteins NSF and SNAP. This so called fusion complex can then disassemble after ATP hydrolysis mediated by the ATPase NSF in a process that leads to membrane fusion and the release of the vesicle contents. v-SNAREs include proteins homologous to synaptobrevin [ , , ].Structurally the SNARE complex is generally a four-helix bundle comprised of three coiled-coil-forming domains from t-SNAREs and one from v-SNARE. Although sequence similarity in the t- and v-SNARE coiled-coil homology domains are low there is a striking conservation of theso-called heptad repeat that is of central importance in forming a coiled-coil structure. In a coiled-coil motif, seven residues constitute a canonical heptad and are designated 'a' through 'g', with 'a' and 'd' being occupied by hydrophobic residues. The association of the four α-helices in the SNARE fusion complex structure produces highly conserved layers of interacting amino acid side chains in the centre of the four-helix bundle. The centre of the bundle is made up of 15 hydrophobic layers from the 'a' and 'd' positions of the heptad repeats of the coiled-coil-forming domains, whereas the central 'ionic' layer is highly conserved and polar in nature, containing a glutamine residue in the three t-SNAREs and an arginine in the v-SNARE, hence the classification of v- and t-SNAREs as R- and Q-SNAREs, respectively. The v-SNARE coiled-coil homology domain is around 60 amino acids in length [, , ].The entry represents the entire v-SNARE coiled-coil homology domain.
Short Name	V_SNARE_CC