Function of microcompartments in the metabolism of ethanolamine in Salmonella enterica

The enzymes that catabolize ethanolamine in Salmonella enterica are held within a protein cage known as the microcompartment. It is not understood how this cage restricts movement of metabolites or how the cage contributes physiologically to growth on ethanolamine. In this dissertation, the role of microcompartments in the metabolism of ethanolamine will be examined genetically. We propose a new view of the ethanolamine breakdown pathway and the intimate involvement of the compartment in this pathway. Results suggest that the compartment contributes to ethanolamine breakdown by preventing loss of the volatile intermediate acetealdehyde. The compartment may accelerate the breakdown of this confined intermediate by providing high local concentrations of enzymes and their cofactors, which are held as private pools and recycled within the compartment. Growth phenotypes of mutants lacking various compartment shell proteins are demonstrated in several distinct ways and suppressors of those phenotypes are discussed.