4Y21:
reference: Syntaxin opening by the MUN domain underlies the function of Munc13 in synaptic-vesicle priming., Yang X, Wang S, Sheng Y, Zhang M, Zou W, Wu L, Kang L, Rizo J, Zhang R, Xu T, Ma C, Nat Struct Mol Biol. 2015 Jul;22(7):547-54. doi: 10.1038/nsmb.3038. Epub 2015 Jun, 1. PMID: 26030875

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