6BJK:
reference: Conserved residues Arg188 and Asp302 are critical for active site organization and catalysis in human ABO(H) blood group A and B glycosyltransferases., Gagnon SML, Legg MSG, Polakowski R, Letts JA, Persson M, Lin S, Zheng RB, Rempel B, Schuman B, Haji-Ghassemi O, Borisova SN, Palcic MM, Evans SV, Glycobiology. 2018 Aug 1;28(8):624-636. doi: 10.1093/glycob/cwy051. PMID: 29873711

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