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Monitoring Intraspecies Competition in a Bacterial Cell Population by Cocultivation of Fluorescently Labelled Strains
Published on: January 18, 2014
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Seven enzymes create extraordinary molecular complexity in an uncultivated bacterium
Michael F Freeman1,2, Maximilian J Helf1, Agneya Bhushan1
1Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
Nature Chemistry
|March 25, 2017
Summary
Seven enzymes are key to producing polytheonamides, complex toxins from uncultivated bacteria. This study deciphers the post-translational modification pathway for these unique amino acid-derived biomolecules.
Area of Science:
- Biochemistry
- Microbiology
- Marine Biology
Background:
- Uncultivated bacteria are a rich source of novel enzymes and metabolites.
- Polytheonamides are potent peptide cytotoxins from marine sponge symbionts.
- These molecules are among the most heavily post-translationally modified biomolecules derived from amino acids.
Purpose of the Study:
- To identify the minimal enzyme set responsible for polytheonamide biosynthesis.
- To elucidate the post-translational modification pathway of polytheonamides.
- To understand the function of cobalamin-dependent C-methyltransferases in this process.
Main Methods:
- Functional enzyme assays using a heterologous host (Rhizobium leguminosarum).
- Systematic observation of post-translational modifications.
- Reconstitution of C-methylation using specific enzymes.
Main Results:
- Identified seven essential enzymes for polytheonamide biosynthesis.
- Demonstrated iterative catalysis of epimerization, methylation, and hydroxylation.
- Observed 44 modifications, unraveling the pathway for a complex biomolecule.
Conclusions:
- A small set of enzymes can achieve extensive post-translational modifications.
- The study provides a framework for understanding the biosynthesis of densely modified natural products.
- This work sheds light on the functional roles of uncultivated bacterial symbionts.
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