A protein complex involved in membrane fusion; a stable ternary complex consisting of a four-helix bundle, usually formed from one R-SNARE and three Q-SNAREs with an ionic layer sandwiched between hydrophobic layers. One well-characterized example is the neuronal SNARE complex formed of synaptobrevin 2, syntaxin 1a, and SNAP-25. [ http://www.ncbi.nlm.nih.gov/pubmed/10872468 http://www.ncbi.nlm.nih.gov/pubmed/19450911 ]