ACT_SITE 710; /note="Charge relay system"; /evidence="ECO:0000250|UniProtKB:P04035"; ACT_SITE 844; /note="Charge relay system"; /evidence="ECO:0000250|UniProtKB:P04035"; ACT_SITE 920; /note="Charge relay system"; /evidence="ECO:0000250|UniProtKB:P04035"; ACT_SITE 1016; /note="Proton donor"; /evidence="ECO:0000255|PROSITE-ProRule:PRU10003"