Nanoscale Enzymatic Compartments in Tandem Support Cascade Reactions in Vitro

Compartmentalization at the nanoscale is fundamental in nature, where the spatial segregation of biochemical reactions within cells ensures optimal conditions for regulating metabolic pathways. Here, we present a nature-inspired approach to engineer enzymatic cascade reactions taking place between separate vesicular nanocompartments (polymersomes), each containing one enzyme type. We propose, by the selected combination of enzymes, an efficient solution to detoxify the harmful effect of uric acid and prevent the accumulation of the derived H2O2, both being associated with various pathological conditions (e.g., gout and oxidative stress). Fungal uricase and horseradish peroxidase combined to act in tandem, and they were separately encapsulated within nanocompartments that were equipped with channel porins as gates to allow passage of substrates and products from each step of the reaction. We established the molecular factors affecting the efficiency of the overall reaction, and the protective role of the compartments. Interestingly, the cascade reaction between separate nanocompartments was as efficient as for free enzymes in complex media, such as human serum. The nanocompartments were nontoxic toward cells, and more importantly, addition of the tandem catalytic nanocompartments to cells exposed to uric acid provided simultaneous detoxification of uric acid and the H2O2. Such catalytic nanocompartments can be used as a platform for understanding fundamental factors affecting intracellular communication and can introduce non-native metabolic reactions into living systems for therapeutic applications.