ACT_SITE 55; /note="Nucleophile"; /evidence="ECO:0000305"; ACT_SITE 58; /note="Nucleophile"; /evidence="ECO:0000305"; ACT_SITE 186; /note="Nucleophile"; /evidence="ECO:0000305"; ACT_SITE 189; /note="Nucleophile"; /evidence="ECO:0000305"