Elucidating and exploiting docking domain-mediated carrier protein recognition in natural product megasynthetases

点击翻译按钮获取中文摘要

Bioactive natural products from plants and microorganisms have numerous important applications in medicine and agriculture. They are used to tackle life-threating conditions, such as bacterial and fungal infections, organ transplant rejection and cancer, and as herbicides, insecticides and fungicides that play an essential role in the protection of food crops. Many natural products are assembled by enzymatic "assembly lines", akin to a car production line. Each component of the assembly line must engage in effective communication with the next to ensure the overall process is efficient. Such communication is typically mediated by dedicated "docking domains" attached to the ends of the components, which interact with each other in a specific way. We have been studying the role played by a particular type of docking domain and its interaction partner in the assembly of enacyloxin IIa. This antibiotic is produced by Burkholderia species and has potent activity against Acinetobacter baumannii, a bacterium that causes life threatening diseases in humans for which there is a critical need to find effective new treatments. Our data have shown that this type of docking domain is involved in the assembly of many more bioactive natural products than previously thought, including several anti-cancer agents and an antibiotic that are used in the clinic. In this project we aim to use a combination of established and recently-developed techniques to develop a better understanding of the way the docking domain involved in the production of enacyloxin recognises its interaction partner. The insights we obtain will be used to modify the enacyloxin assembly line to see whether it behaves in the way we predict. We also aim to investigate a related system in which two components, both of which have a docking domain that is similar to the one involved in enacyloxin production, appear to interact with the same partner to execute sequential tasks in the assembly of the aeruginosins, an unusual group of protein degradation inhibitors produced by cyanobacteria. This will broaden our understanding of the role played by docking domains in natural product assembly and allow us to establish the common principles underlying the way in which they recognise their interaction partners. Finally, we will investigate whether our understanding of these common principles can be harnessed to substitute one of the components of the aeruginosin assembly line with the corresponding component from the enacyloxin system. Overall, this project will significantly deepen our understanding of the roles played by an important type of docking domain in natural product assembly and will establish the feasibility of exploiting such docking domains to construct engineered assembly lines capable of producing novel natural product hybrids.