3MHZ:
reference: Evidence that histidine protonation of receptor-bound anthrax protective antigen is a trigger for pore formation., Wimalasena DS, Janowiak BE, Lovell S, Miyagi M, Sun J, Zhou H, Hajduch J, Pooput C, Kirk KL, Battaile KP, Bann JG, Biochemistry. 2010 Aug 24;49(33):6973-83. PMID: 20672855

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