title: Characterization of AmtA, an amidinotransferase involved in the biosynthesis of phaseolotoxins.
abstract: Phaseolotoxins (PHTs), which are produced by Pseudomonas, belong to a family of phosphoramidate natural products. Two nonproteinogenic amino acid precursors, N(δ)(N'-sulfo-diaminophosphinyl)-ornithine (PSOrn) and homoarginine (hArg), are involved in biosynthesis of PHTs. Amidinotransferase AmtA catalyses the formation of hArg, with arginine and lysine as substrates. AmtA was overexpressed and purified in an Escherichia coli system. An in vitro enzyme assay showed that it has stricter substrate specificity than certain other amidinotransferases. Site-directed mutagenesis experiments showed that the mutation AmtA Met243His244 is an alternative while Met246 is essential for the transamidination activity.
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education School of Pharmaceutical Sciences Wuhan University China.
authors.forename: Mi
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education School of Pharmaceutical Sciences Wuhan University China.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education School of Pharmaceutical Sciences Wuhan University China.
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education School of Pharmaceutical Sciences Wuhan University China.
authors.forename: Changming
authors.initials: C
authors.lastname: Zhao
keywords: amidinotransferase; biosynthesis; homoarginine; phaseolotoxin