Biogenesis of a bacterial metabolosome for propanediol utilization.

Bacterial metabolosomes are a family of protein organelles in bacteria. Elucidating how thousands of proteins self-assemble to form functional metabolosomes is essential for understanding their significance in cellular metabolism and pathogenesis. Here we investigate the de novo biogenesis of propanediol-utilization (Pdu) metabolosomes and characterize the roles of the key constituents in generation and intracellular positioning of functional metabolosomes. Our results demonstrate that the Pdu metabolosome undertakes both "Shell first" and "Cargo first" assembly pathways, unlike the β-carboxysome structural analog which only involves the "Cargo first" strategy. Shell and cargo assemblies occur independently at the cell poles. The internal cargo core is formed through the ordered assembly of multiple enzyme complexes, and exhibits liquid-like properties within the metabolosome architecture. Our findings provide mechanistic insight into the molecular principles driving bacterial metabolosome assembly and expand our understanding of liquid-like organelle biogenesis. Bacteria have evolved proteinaceous microcompartments (BMCs) to control the passage of metabolites and facilitate catabolism in a micro-environment. Here, Yang et al. apply fluorescence microscopy to characterize the protein-protein interaction and assembly involved in the de novo biogenesis of propanediol-utilization (Pdu) metabolosomes and show that Pdu BMCs undergo a combination of 'Shell first' and 'Cargo first' assembly. [ABSTRACT FROM AUTHOR]