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Matabaro E, Song H, Chepkirui C, Kaspar H, Witte L, Naismith JH, Freeman MF, Künzler M. Enzyme-mediated backbone N-methylation in ribosomally encoded peptides. Methods Enzymol 2021; 656:429-458. [PMID: 34325794 DOI: 10.1016/bs.mie.2021.04.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Backbone N-methylation as a posttranslational modification was recently discovered in a class of ribosomally encoded peptides referred to as borosins. The founding members of the borosins are the omphalotins (A-I), backbone N-methylated, macrocyclic dodecapeptides produced by the mushroom Omphalotus olearius. Omphalotins display a strong and selective toxicity toward the plant parasitic nematode Meloidogyne incognita. The primary product omphalotin A is synthesized via a concerted action of the omphalotin precursor protein (OphMA) and the dual function prolyloligopeptidase/macrocyclase (OphP). OphMA consists of α-N-methyltransferase domain that autocatalytically methylates the core peptide fused to its C-terminus via a clasp domain. Genome mining uncovered over 50 OphMA homologs from the fungal phyla Ascomycota and Basidiomycota. However, the derived peptide natural products have not been described yet, except for lentinulins, dendrothelins and gymnopeptides produced by the basidiomycetes Lentinula edodes, Dendrothele bispora and Gymnopus fusipes, respectively. In this chapter, we describe methods used to isolate and characterize these backbone N-methylated peptides and their precursor proteins both in their original hosts and in the heterologous hosts Escherichia coli and Pichia pastoris. These methods may pave the path for both the discovery of novel borosins with interesting bioactivities. In addition, understanding of borosin biosynthetic pathways may allow setting up a biotechnological platform for the production of pharmaceutical leads for orally available peptide drugs.
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Affiliation(s)
- Emmanuel Matabaro
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Haigang Song
- The Research Complex at Harwell, Harwell Campus, Didcot, United Kingdom; The Rosalind Franklin Institute, Harwell Campus, Didcot, United Kingdom
| | - Clara Chepkirui
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Hannelore Kaspar
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Luca Witte
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - James H Naismith
- Division of Structural Biology, Wellcome Centre for Human Genetics, Oxford, United Kingdom; The Research Complex at Harwell, Harwell Campus, Didcot, United Kingdom; The Rosalind Franklin Institute, Harwell Campus, Didcot, United Kingdom
| | - Michael F Freeman
- Department of Biochemistry, Molecular Biology, and Biophysics and BioTechnology Institute, University of Minnesota-Twin Cities, St. Paul, Minnesota, United States
| | - Markus Künzler
- Department of Biology, Institute of Microbiology, ETH Zürich, Zürich, Switzerland.
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Vogt E, Künzler M. Discovery of novel fungal RiPP biosynthetic pathways and their application for the development of peptide therapeutics. Appl Microbiol Biotechnol 2019; 103:5567-5581. [PMID: 31147756 DOI: 10.1007/s00253-019-09893-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/06/2019] [Accepted: 05/06/2019] [Indexed: 12/18/2022]
Abstract
Bioactive peptide natural products are an important source of therapeutics. Prominent examples are the antibiotic penicillin and the immunosuppressant cyclosporine which are both produced by fungi and have revolutionized modern medicine. Peptide biosynthesis can occur either non-ribosomally via large enzymes referred to as non-ribosomal peptide synthetases (NRPS) or ribosomally. Ribosomal peptides are synthesized as part of a larger precursor peptide where they are posttranslationally modified and subsequently proteolytically released. Such peptide natural products are referred to as ribosomally synthesized and posttranslationally modified peptides (RiPPs). Their biosynthetic pathways have recently received a lot of attention, both from a basic and applied research point of view, due to the discoveries of several novel posttranslational modifications of the peptide backbone. Some of these modifications were so far only known from NRPSs and significantly increase the chemical space covered by this class of peptide natural products. Latter feature, in combination with the promiscuity of the modifying enzymes and the genetic encoding of the peptide sequence, makes RiPP biosynthetic pathways attractive for synthetic biology approaches to identify novel peptide therapeutics via screening of de novo generated peptide libraries and, thus, exploit bioactive peptide natural products beyond their direct use as therapeutics. This review focuses on the recent discovery and characterization of novel RiPP biosynthetic pathways in fungi and their possible application for the development of novel peptide therapeutics.
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Affiliation(s)
- Eva Vogt
- ETH Zürich, Department of Biology, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland
| | - Markus Künzler
- ETH Zürich, Department of Biology, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland.
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