Genetic analyses reveal distinct functional roles of Eut microcompartment shell proteins in ethanolamine metabolism in Salmonella

Abstract

Ethanolamine utilization is an important metabolic capability of enteric bacteria and has been associated with bacterial fitness and adaptation within diverse host environment. In Salmonella enterica serovar Typhimurium, ethanolamine is metabolized within the bacterial microcompartment (Eut MCP), which is composed of five shell protein subunits. Deciphering how self-assembled shell proteins spatially organize the pathway, retain metabolic intermediates and create proper environment for catalysis is crucial for understanding role of Eut MCP in cellular metabolism and pathogenesis. Through genetic mutant construction, growth and metabolic assays, microscopy, and metabolite quantification, we demonstrate that each shell protein fulfills a distinct role to the functioning of the Eut MCP. Our findings provide mechanistic insights into the structural organization and functional dynamics of the bacterial microcompartment organelle.