1N4X:
reference: Structure of a single-chain Fv fragment of an antibody that inhibits the HIV-1 and HIV-2 proteases., Lescar J, Brynda J, Fabry M, Horejsi M, Rezacova P, Sedlacek J, Bentley GA, Acta Crystallogr D Biol Crystallogr 2003 May;59(Pt 5):955-7. PMID: 12777823

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