3KNE:
reference: Stereo- and Regioselective Azide/Alkyne Cycloadditions in Carbonic Anhydrase II via Tethering, Monitored by Crystallography and Mass Spectrometry., Schulze Wischeler J, Sun D, Sandner NU, Linne U, Heine A, Koert U, Klebe G, Chemistry. 2011 May 16;17(21):5842-51. doi: 10.1002/chem.201002437. Epub, 2011 Apr 19. PMID: 21506176

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