1GI9:
reference: A novel serine protease inhibition motif involving a multi-centered short hydrogen bonding network at the active site., Katz BA, Elrod K, Luong C, Rice MJ, Mackman RL, Sprengeler PA, Spencer J, Hataye J, Janc J, Link J, Litvak J, Rai R, Rice K, Sideris S, Verner E, Young W, J Mol Biol 2001 Apr 13;307(5):1451-86. PMID: 11292354

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