3ZUR:
reference: Structures of engineered Clostridium botulinum neurotoxin derivatives., Masuyer G, Stancombe P, Chaddock JA, Acharya KR, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 Dec 1;67(Pt 12):1466-72., Epub 2011 Nov 25. PMID: 22139146

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