Prokaryotic Organelles: Bacterial Microcompartments in E. coli and Salmonella

Abstract

Bacterial microcompartments (MCPs) are proteinaceous organelles consisting of a metabolic pathway encapsulated within a selectively permeable protein shell. Hundreds of species of bacteria produce MCPs of at least nine different types, and MCP metabolism is associated with enteric pathogenesis, cancer, and heart disease. This review focuses chiefly on the four types of catabolic MCPs (metabolosomes) found in Escherichia coli and Salmonella : the propanediol utilization ( pdu ), ethanolamine utilization ( eut ), choline utilization ( cut ), and glycyl radical propanediol ( grp ) MCPs. Although the great majority of work done on catabolic MCPs has been carried out with Salmonella and E. coli , research outside the group is mentioned where necessary for a comprehensive understanding. Salient characteristics found across MCPs are discussed, including enzymatic reactions and shell composition, with particular attention paid to key differences between classes of MCPs. We also highlight relevant research on the dynamic processes of MCP assembly, protein targeting, and the mechanisms that underlie selective permeability. Lastly, we discuss emerging biotechnology applications based on MCP principles and point out challenges, unanswered questions, and future directions.

Bacterial Microcompartments Coupled with Extracellular Electron Transfer Drive the Anaerobic Utilization of Ethanolamine in Listeria monocytogenes

“…According to current models, EA is catabolized to acetate and ethanol in a molar ratio of 1:1 via the oxidative ATP-producing branch and reductive NAD + -regenerating branch ( 6 ). Interestingly, previous studies showed that EA confers a marked anaerobic growth advantage on Salmonella enterica serovar Typhimurium only in the presence of tetrathionate, acting as an alternative electron acceptor via tetrathionate reductase ( 6 , 14 – 16 ), and the mutant lacking the tetrathionate reductase showed a decreasing colonization capacity in a mouse colitis model, which points to a role for anaerobic electron transfer in EA catabolism contributing to the growth of S. enterica in the lumen of the inflamed intestine ( 15 ). Anaerobic EA catabolism in L. monocytogenes , including possible roles for anaerobic respiration, has not been studied.…”

Computational Modeling and Evolutionary Implications of Biochemical Reactions in Bacterial Microcompartments

“…Recent reviews have delved into a wide variety of topics such as BMC positioning [5], BMC repurposing for industrial uses [6], evolutionary relationship of shell proteins across different BMCs [7], and BMC protein stoichiometry [8,9]. [10][11][12][13]. The charge of each metabolite is indicated with color; positive in red, negative in blue, and neutral in grey.…”

“…Figure 1. Diagram of the substrates, intermediates, and products of carboxysomes and the most studied catabolic BMCs[10][11][12][13]. The charge of each metabolite is indicated with color; positive in red, negative in blue, and neutral in grey.…”

Linking the Salmonella enterica 1,2-propanediol utilization bacterial microcompartment shell to the enzymatic core via the shell protein PduB

“…One of the most well-studied types of metabolosomes is the 1,2-propanediol utilization (Pdu) MCP found in Salmonella enterica serovar Typhimurium LT2 (hereafter referred to as "LT2"). The Pdu MCP provides an excellent model for metabolosome 5 study as Pdu MCPs natively exist in a number of model bacterial hosts such as the aforementioned LT2 as well as strains of Escherichia coli (11). Pdu MCPs are broadly distributed throughout many bacterial phyla and numerous Pdu subtypes exist (12)(13)(14).…”