1R4Z:
reference: Directed Evolution of Bacillus subtilis Lipase A by Use of Enantiomeric Phosphonate Inhibitors: Crystal Structures and Phage Display Selection., Droge MJ, Boersma YL, van Pouderoyen G, Vrenken TE, Ruggeberg CJ, Reetz MT, Dijkstra BW, Quax WJ, Chembiochem. 2006 Jan 9;7(1):149-157. PMID: 16342303

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