Elucidating the biosynthetic pathway of the saccharomicins – New antibiotics from Saccharothrix Espanaensis

The discovery of new antibiotics is an essential approach to effectively combat multidrug-resistant pathogens. The saccharomicins A and B, produced by the soil-dwelling bacterium Saccharothrix espanaensis, comprise a new class of heptadecaglycoside antibiotics with activity against MRSA and VRE.

The complete genome sequence of Saccharothrix espanaensis revealed the entire gene cluster of the saccharomicins 1. Annotation of the cluster led to a putative pathway for the synthesis of the exceptional aglycon N-(3,4-dihydroxycinnamoyl)-taurine. To verify this hypothesis, genes from the cluster were expressed in a heterologous host leading to the partial synthesis of the aglycon. Additionally, the genes responsible for the synthesis and attachment of the sugar moieties were heterologously expressed and checked for biotransformation of the fed caffeic acid, a component of the aglycon.

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