5VGV:
reference: Metal Ions Effectively Ablate the Action of Botulinum Neurotoxin A., Bremer PT, Pellett S, Carolan JP, Tepp WH, Eubanks LM, Allen KN, Johnson EA, Janda KD, J Am Chem Soc. 2017 May 31;139(21):7264-7272. doi: 10.1021/jacs.7b01084. Epub, 2017 May 19. PMID: 28475321

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