Engineering an Artificial Myxopyronin Derivative with Enhanced Metabolic Stability via Mutasynthesis

The rise of multidrug-resistant pathogens, such as Staphylococcus aureus and Mycobacterium tuberculosis, underscores an urgent need for therapeutic innovation. The antibiotic development pipeline targeting these bacteria is critically limited, with most discovered candidates exhibiting structurally similar features of prominent chemical entities, with well-established molecular targets or binding modes. The myxobacterial α-pyrone antibiotics, myxopyronins, represent a highly promising compound class due to their ability to inhibit RNA polymerase by binding to the "switch region", a distinct binding site to that of standard-of-care antibiotics. Although total synthesis has enabled access to the natural products, this strategy faces significant limitations to generate analogs. Mutasynthesis, leveraging engineered microorganisms and tailored precursors, provides a viable alternative to generate novel derivatives. This study utilized a heterologous expression system in Myxococcus xanthus DK1622 to generate analogs. Two carrier protein domain mutants were engineered to facilitate mutasynthesis-based production of structurally diverse derivatives. A trifluoromethyl-modified analog demonstrated potent antimicrobial activity against Gram-positive pathogens including Mycobacterium tuberculosis and favorable in vitro absorption, distribution, metabolism, excretion and toxicity properties. These findings highlight a promising pathway for developing optimized α pyrone antibiotics to address the global antimicrobial-resistance crisis.