"Zytnick et al. explicitly refer to **“putative acetyltransferase mllH (META1p4137)”** in *Methylobacterium/Methylorubrum extorquens* AM1"

"Zytnick et al. describe an **mll biosynthetic gene cluster spanning META1p4129–META1p4138** in *M. extorquens* AM1, responsible for production of a lanthanide-binding metallophore named **methylolanthanin (MLL)**"

"it contains a **central citrate** linked to **two 4-hydroxybenzoate moieties via acetylated homospermidine residues**"

"**mllH (META1p4137)** is annotated as a **putative acetyltransferase**, and Zytnick et al. state that its presence suggested incorporation of an **acetylated (homo)spermidine linker**, by analogy to rhodopetrobactin-like pathways"

"mllH is not biochemically characterized at the single-enzyme level"

"no purified enzyme assay, no confirmed substrate range/kinetics, no gene-specific knockout phenotype reported"

"the most conservative current annotation is that MllH acts **intracellularly (likely cytosolic)** during methylolanthanin biosynthesis"

"mllH is embedded in a functional lanthanophore pathway and should be interpreted primarily as a **biosynthetic accessory enzyme**, not as a global protein acetyltransferase"

"META1p4137 (mllH) is homologous to genes involved in rhodopetrobactin biosynthesis"

"The presence of mllH suggests incorporation of acetylated homospermidine linker"