3AXC:
reference: Structure of a compact conformation of linear diubiquitin., Rohaim A, Kawasaki M, Kato R, Dikic I, Wakatsuki S, Acta Crystallogr D Biol Crystallogr. 2012 Feb;68(Pt 2):102-8. Epub 2012 Jan 13. PMID: 22281738

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