5C9B:
reference: Structure of RC1339/APRc from Rickettsia conorii, a retropepsin-like aspartic protease., Li M, Gustchina A, Cruz R, Simoes M, Curto P, Martinez J, Faro C, Simoes I, Wlodawer A, Acta Crystallogr D Biol Crystallogr. 2015 Oct;71(Pt 10):2109-18. doi:, 10.1107/S1399004715013905. Epub 2015 Sep 30. PMID: 26457434

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