Total Biosynthesis of the Pyrrolo[4,2]benzodiazepine Scaffold Tomaymycin on an In Vitro Reconstituted NRPS System.
Cell Chem Biol 2017;
24:1216-1227.e8. [PMID:
28890318 DOI:
10.1016/j.chembiol.2017.08.001]
[Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/19/2017] [Accepted: 08/01/2017] [Indexed: 11/25/2022]
Abstract
In vitro reconstitution and biochemical analysis of natural product biosynthetic pathways remains a challenging endeavor, especially if megaenzymes of the nonribosomal peptide synthetase (NRPS) type are involved. In theory, all biosynthetic steps may be deciphered using mass spectrometry (MS)-based analyses of both the carrier protein-coupled intermediates and the free intermediates. We here report the "total biosynthesis" of the pyrrolo[4,2]benzodiazepine scaffold tomaymycin using an in vitro reconstituted NRPS system. Proteoforms were analyzed by liquid chromatography (LC)-MS to decipher every step of the biosynthesis on its respective megasynthetase with up to 170 kDa in size. To the best of our knowledge, this is the first report of a comprehensive analysis of virtually all chemical steps involved in the biosynthesis of nonribosomally synthesized natural products. The study includes experiments to determine substrate specificities of the corresponding A-domains in competition assays by analyzing the adenylation step as well as the transfer to the respective carrier protein domain.
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