Members of this family are involved in synthesizing N-hydroxyhistamine as a precursor to acinetobactin, a siderophore found in Acinetobacter baumannii. Assuming histidine is first decarboxylated to histamine, then hydroxylated, members of this family are histamine N-monooxygenase. The putative histidine decarboxylase is found in the same biosynthetic cluster.
Jiyao W et al.(2023). "The conserved domain database in 2023.",