1BPT:
reference: Crevice-forming mutants in the rigid core of bovine pancreatic trypsin inhibitor: crystal structures of F22A, Y23A, N43G, and F45A., Danishefsky AT, Housset D, Kim KS, Tao F, Fuchs J, Woodward C, Wlodawer A, Protein Sci 1993 Apr;2(4):577-87. PMID: 8518731

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