Volume 62, Issue 35 e202304843
Communication
Open Access

Directed Evolution of Piperazic Acid Incorporation by a Nonribosomal Peptide Synthetase**

Philipp Stephan

Philipp Stephan

Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany

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Chloe Langley

Chloe Langley

Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany

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Daniela Winkler

Daniela Winkler

Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany

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Dr. Jérôme Basquin

Dr. Jérôme Basquin

Department of Structural Cell Biology, Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Planegg Martinsried, Germany

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Dr. Lorenzo Caputi

Dr. Lorenzo Caputi

Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany

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Prof. Dr. Sarah E. O'Connor

Prof. Dr. Sarah E. O'Connor

Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany

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Dr. Hajo Kries

Corresponding Author

Dr. Hajo Kries

Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany

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First published: 16 June 2023
Citations: 6
**

A previous version of this manuscript has been deposited on a preprint server (https://doi.org/10.1101/2023.04.03.535426).

Graphical Abstract

Efficient directed evolution protocols for nonribosomal peptide synthetases are needed to adapt the structures of antibiotic peptides for the fight against antimicrobial resistance. Here, an easily reproducible directed evolution protocol was used to reprogram the synthetase for the antibiotic peptide gramicidin S. A few mutations were sufficient to incorporate the non-standard building block piperazic acid instead of proline with perfect specificity.

Abstract

Engineering of biosynthetic enzymes is increasingly employed to synthesize structural analogues of antibiotics. Of special interest are nonribosomal peptide synthetases (NRPSs) responsible for the production of important antimicrobial peptides. Here, directed evolution of an adenylation domain of a Pro-specific NRPS module completely switched substrate specificity to the non-standard amino acid piperazic acid (Piz) bearing a labile N−N bond. This success was achieved by UPLC-MS/MS-based screening of small, rationally designed mutant libraries and can presumably be replicated with a larger number of substrates and NRPS modules. The evolved NRPS produces a Piz-derived gramicidin S analogue. Thus, we give new impetus to the too-early dismissed idea that widely accessible low-throughput methods can switch the specificity of NRPSs in a biosynthetically useful fashion.

Data Availability Statement

The coordinates and reflection data of the crystal structure described in this manuscript are available in the Protein Data Bank (PDB ID: 8P5O). Further primary data are shown in the Supporting Information and are available from the authors upon request.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.