5E5K:
reference: Long-Range Electrostatics-Induced Two-Proton Transfer Captured by Neutron Crystallography in an Enzyme Catalytic Site., Gerlits O, Wymore T, Das A, Shen CH, Parks JM, Smith JC, Weiss KL, Keen DA, Blakeley MP, Louis JM, Langan P, Weber IT, Kovalevsky A, Angew Chem Int Ed Engl. 2016 Apr 11;55(16):4924-7. doi: 10.1002/anie.201509989., Epub 2016 Mar 9. PMID: 26958828

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