PS50892

v-SNARE coiled-coil homology domain profile

PROSITE profiles entry
Member databasePROSITE profiles
PROSITE profiles typedomain
Short nameV_SNARE

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
[2]
[3]
[1]
. 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 the so-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 alpha-helices in the SNARE fusion complex structure produces highly conserved layers of interacting amino acid side chains in the center of the four-helix bundle. The center 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
[2]
[3]
[1]
. The profile we developed cover the entire v-SNARE coiled-coil homology domain.

References

1.Amisyn, a novel syntaxin-binding protein that may regulate SNARE complex assembly. Scales SJ, Hesser BA, Masuda ES, Scheller RH. J. Biol. Chem. 277, 28271-9, (2002). View articlePMID: 12145319

2.Phylogenetic analysis of membrane trafficking proteins: a family reunion and secondary structure predictions. Terrian DM, White MK. Eur. J. Cell Biol. 73, 198-204, (1997). PMID: 9243180

3.Conserved structural features of the synaptic fusion complex: SNARE proteins reclassified as Q- and R-SNAREs. Fasshauer D, Sutton RB, Brunger AT, Jahn R. Proc. Natl. Acad. Sci. U.S.A. 95, 15781-6, (1998). View articlePMID: 9861047

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