This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Excitation and Action Potiential, Subject name: Physiology
Tetanus toxin acts on which of the following synaptic protein 
Select and explain. 
A. R-SNARE, B. Q-SNARE, C. SNAP25, D. Rab and Munc 18
A: R-SNARE
Answer: A: R-SNARE 
Explanation: Tetanus toxin cleaves synaptobrevin-2 . Synaptobrevin is a R-SNARE protein also known as Vesicle Associated Membrane Protein(VAMP) Q-SNARE proteins are syntaxin (Qa), SNAP25(Qb & Qc)and SM protein (Munc18) Botulinum toxin (BT) serotype A, B and E are toxic to humans. BT-A, BT-E cleaves SNAP25, BT-C cleaves both SNAP25 and syntaxin. BT-B, BT-D, BT-F, BT-G cleaves synaptobrevin- 2 (VAMP-2)