1ZGU:
reference: Structural Basis for Non-Covalent Interaction Between Ubiquitin and the Ubiquitin Conjugating Enzyme Variant Human MMS2., Lewis MJ, Saltibus LF, Hau DD, Xiao W, Spyracopoulos L, J Biomol NMR. 2006 Feb;34(2):89-100. PMID: 16518696

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