Abstract
Over the past 50 years, more than 15 pharmaceuticals derived from marine organisms have come to the market. Most of these come from filter-feeding invertebrates that contain a high proportion of microbial symbionts. Microbiology and molecular genetic studies have shown that many of these drug-like compounds are produced by the microbial symbiont. The enzymes that produce these compounds are promiscuous meaning they can process a diverse range of related substrates, making them extremely attractive to the biotechnology industry. Determining the structure of these enzymes makes them amenable to engineering, allowing them to process non-natural substrates. Using this approach, synthetic substrates can be treated with a cocktail of enzymes to prepare focused libraries of compounds to hit drug targets such as protein–protein interactions. These targets are involved in a range of diseases from cancer to immune disorders and are hard to modulate using small molecule drugs. Complex modified cyclic peptides produced using a chemoenzymatic process may be a promising approach to address these disease conditions.