Function 
Syntaxin-binding proteins (STXBP) are involved in the regulation of synaptic vesicle docking and fusion.  STXBP1 participates in synaptic vesicle fusion via dual roles: as a docking/chaperone protein by binding Syntaxin-1 and as a fusion protein that binds SNARE complexes in a Syntaxin-1 N-peptide-dependent manner[1].  STXBP2 binds SNARE proteins.
  Structural highlights 
Syntaxin-binding protein 1 interaction with the N-terminal peptide of syntaxin-1 which forms part of the SNARE complex shows the peptide forming a tight loop with numerous intermolecular hydrogen bonds.  The STXBP1 and the syntaxin peptide interact via numerous electrostatic and polar interactions[1].