Tundrenone: An Atypical Secondary Metabolite from Bacteria with Highly Restricted Primary Metabolism

Methane-oxidizing bacteria, aerobes that utilize methane as their sole carbon and energy source, are being increasingly studied for their environmentally significant ability to remove methane from the atmosphere. Their genomes indicate that they also have a robust and unusual secondary metabolism. Bioinformatic analysis of the Methylobacter tundripaludum genome identified biosynthetic gene clusters for several intriguing metabolites, and this report discloses the structural and genetic characterization of tundrenone, one of these metabolites. Tundrenone is a highly oxidized metabolite that incorporates both a modified bicyclic chorismate-derived fragment and a modified lipid tail bearing a β,γ-unsaturated α-hydroxy ketone. Tundrenone has been genetically linked to its biosynthetic gene cluster, and quorum sensing activates its production. M. tundripaludum's genome and tundrenone's discovery support the idea that additional studies of methane-oxidizing bacteria will reveal new naturally occurring molecular scaffolds and the biosynthetic pathways that produce them.