The Wrappers of the 1,2-Propanediol Utilization Bacterial Microcompartments.

The propanediol utilization bacterial microcompartments are specialized protein-based organelles in Salmonella that facilitate the catabolism of 1,2-propanediol when available as the sole carbon source. This smart prokaryotic cell organelle compartmentalizes essential enzymes and substrates in a volume of a few attoliters compared to the femtoliter volume of a bacterial cell thereby enhancing the enzyme kinetics and properly orchestrating the downstream pathways. A shell or coat, which is composed of a few thousand protein subunits, wraps a chain of consecutively acting enzymes and serves as ducts for the diffusion of substrates, cofactors, and products into and out of the core of the microcompartment. In this article we bring together the properties of the wrappers of the propanediol utilization bacterial microcompartments to update our understanding on the mechanism of the formation of these unique wraps, their assembly, and interaction with the encapsulated enzymes.