Neighbor-Joining tree of flavin-dependent halogenases associated with characterized secondary metabolites. On each of the corresponding secondary metabolite, the site of halogenation is indicated. Red branches correspond to halogenases that modify acyl carrier protein bound substrates, and green branches correspond to enzymes that halogenate free substrates. The blue branch is occupied by Amm3, described in this work, and MibH, a halogenase that likely modifies a tryptophan embedded in a peptide substrate. MUSCLE alignment and phylogenetic tree were generated using Geneious 8.1.5.