Biosynthesis of the Antiviral and Antifungal Pradimicin
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: There are over 40 million people living with HIV/AIDS in the world today, with five million new cases reported every year. Over three million people die from the complication per year, among which half a million are children. Developing effective therapeutic options to prevent HIV infection and combat AIDS-related infectious diseases are therefore one of the most important goals of modern medicine. Research performed in this proposal may lead to the development of novel antiviral/antifungal combination drugs that can be used to prevent and combat AIDS and AIDS induced fungal infections. Our target is the family of compounds known as pradimicins. Pradimicins are produced by soil organism Actinomadura hibisca and has been shown to displays potent antiviral and antifungal activities. Pradimicin is an effective HIV entry inhibitor that blocks the infection of the HIV virus to human T-cells. Pradimicins are also fungicidal against a wide variety of fungi that threaten immunocompromised AIDS patients. The dual bioactivity is especially advantageous for AIDS patients who are infected with fungi or are at risk for fungal infection. Unfortunately, despite the lack of toxicity in animal models, early phase I trials in human volunteers revealed kidney toxicity. As a result, clinical investigation with pradimicin has been discontinued and analogs of pradimicin with improved pharmacological properties are needed. The complexity of the pradimicin molecule has precluded efficient total synthesis and has severely impeded the development of novel pradimicin analogs. We plan to use the emerging, powerful technique of engineered biosynthesis to produce analogs of pradimicin that display enhanced activities and decreased hepatoxicity. Engineered biosynthesis involves the genetic modification of enzymes involved in the biosynthesis of a natural product. The goal of this UARP grant is to lay the foundation for engineered biosynthesis of pradimicin compounds by elucidating the metabolic pathway and reconstitute the pathway in a genetically amendable and high-yielding heterologous host. We will pursue the following aims during this proposal period: 1) Uncover the genetic blueprint for pradimicin biosynthesis. We will identify the biosynthetic gene cluster that encodes the enzymes involved in pradimicin assembly. This is a requirement for the subsequent genetic engineering efforts; 2) Reconstruct the pathway in a more robust host. The original producer A. hibisca is genetically intractable and is difficult to culture. Therefore, we seek to reconstruct the pathway in a heterologous host that is more amendable to genetic engineering. We will use the workhorse organism Streptomyces coelicolor, which has been employed in the engineered biosynthesis of numerous antibiotics, for studying and engineering pradimicin biosynthesis. We have previously demonstrated successful reconstitution of a key early step of pradimicin biosynthesis in S. coelicolor (Lee and Tang, JACS, 2006). During this proposal period, we will expand on these findings and biosynthesize the complete pradimicin compound. Establish a flexible, robust platform for synthesizing and analyzing pradimicin biosynthesis will enable genetic engineering of pradimicin biosynthesis to yield novel unnatural natural products that are more suitable for clinical development as an anti-HIV/antiviral drug.