Botox® is a protease from the bacterium clostridium botulinum. low concentrations of this toxin are commonly used to eliminate wrinkles, because it prevents the secretion of acetylcholine (a neurotransmitter), thus blocking nerve impulses to muscles underneath.
rickman et al. (2004; jbc 279: 644) investigated whether the botulinum toxin had any direct effects on the snares involved in release of acetylcholine. the t-snare, snap-25, forms a dimer with another t-snare (syntaxin, labeled syx) that then binds to the v-snare to allow vesicle fusion. in all cases the scale bar shown is 5 μm.