4EXH:
reference: NX43Inhibition of XMRV and HIV-1 proteases by pepstatin A and acetyl-pepstatin., Matuz K, Motyan J, Li M, Wlodawer A, Tozser J, FEBS J. 2012 Jul 17. doi: 10.1111/j.1742-4658.2012.08714.x. PMID: 22804908

This OCA Structure page
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