ACT_SITE 744; /note="Charge relay system"; /evidence="ECO:0000250|UniProtKB:P04035"; ACT_SITE 877; /note="Charge relay system"; /evidence="ECO:0000250|UniProtKB:P04035"; ACT_SITE 953; /note="Charge relay system"; /evidence="ECO:0000250|UniProtKB:P04035"; ACT_SITE 1049; /note="Proton donor"; /evidence="ECO:0000255|PROSITE-ProRule:PRU10003"