Abstract
Diversification of structurally complex natural products remains a key challenge in the discovery of next-generation therapeutics. Premarineosin A, a potent and selective antimalarial natural product, is a promising yet underexplored scaffold due to its limited availability and synthetic complexity. In this work, we overcome both barriers by coupling metabolic engineering with late-stage derivatization, enabling the first systematic exploration of the premarineosin A scaffold. Rational engineering of Streptomyces eitanensis, encoding a premarineosin A biosynthetic gene cluster, increased titers over 170-fold. Sustainable production of (-)-premarineosin A enabled a unique semi-synthetic and biocatalytic derivatization campaign. In this structure-activity relationship study of premarineosin A, we accessed a suite of analogs, including a C12-brominated derivative with nanomolar potency (EC(50) < 5 nM). This work establishes (-)-premarineosin A as a tractable and evolvable antimalarial scaffold, demonstrating how chemical biology approaches can unlock structural and pharmacological space from complex microbial metabolites.