Ebony, a Novel Nonribosomal Peptide Synthetase for β-Alanine Conjugation with Biogenic Amines in Drosophila

• Published in: The Journal of biological chemistry 2003-10, Vol.278 (42), p.41160
• Main Authors: Arnd Richardt, Tobias Kemme, Stefanie Wagner, Dirk Schwarzer, Mohamed A. Marahiel, Bernhard T. Hovemann
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M304303200

Using Ebony protein either expressed in Escherichia coli or in Schneider S2 cells, we provide evidence for its substrate specificity and reaction mechanism. Ebony activates β-alanine to aminoacyladenylate by an adenylation domain and covalently attaches it as a thioester to a thiolation domain in a n on r ibosomal p eptide s ynthetase (NRPS) related mechanism. In a second reaction, biogenic amines act as external nucleophiles on β-alanyl- S -pantetheine-Ebony, thereby releasing in a fast reaction the dipeptide (peptidoamine) in a process that is novel in higher eucaryotes. Therefore, we define Ebony as a β-alanyl-biogenic amine synthetase. Insight into the reaction mechanism stems from mutational analysis of an invariant serine that disclosed Ebony as a multienzyme with functional analogy to the starting modules of NRPSs. In light of a putative biogenic amine-deactivating capacity, Ebony function in the nervous system must be reconsidered. We propose that in the Drosophila eye Ebony is involved in the transmission process by inactivation of histamine through β-alanyl conjugation.