In Salmonella enterica， 1，2-propanediol (1，2-PD) utilization (Pdu) is mediated by a bacterial microcompartment (MCP). The Pdu MCP consists of a multiprotein shell that encapsulates enzymes and cofactors for 1，2-PD catabolism， and its role is to sequester a reactive intermediate (propionaldehyde) to minimize cellular toxicity and DNA damage. For the Pdu MCP to function， the enzymes encapsulated within must be provided with a steady supply of substrates and cofactors. In the present study， Western blotting assays were used to demonstrate that the PduL phosphotransacylase is a component of the Pdu MCP. We also show that the N-terminal 20-residue-long peptide of PduL is necessary and sufficient for ta... More
In Salmonella enterica， 1，2-propanediol (1，2-PD) utilization (Pdu) is mediated by a bacterial microcompartment (MCP). The Pdu MCP consists of a multiprotein shell that encapsulates enzymes and cofactors for 1，2-PD catabolism， and its role is to sequester a reactive intermediate (propionaldehyde) to minimize cellular toxicity and DNA damage. For the Pdu MCP to function， the enzymes encapsulated within must be provided with a steady supply of substrates and cofactors. In the present study， Western blotting assays were used to demonstrate that the PduL phosphotransacylase is a component of the Pdu MCP. We also show that the N-terminal 20-residue-long peptide of PduL is necessary and sufficient for targeting PduL and enhanced green fluorescent protein (eGFP) to the lumen of the Pdu MCP. We present the results of genetic tests that indicate that PduL plays a role in the recycling of coenzyme A internally within the Pdu MCP. However， the results indicate that some coenzyme A recycling occurs externally to the Pdu MCP. Hence， our results support a model in which a steady supply of coenzyme A is provided to MCP lumen enzymes by internal recycling by PduL as well as by the movement of coenzyme A across the shell by an unknown mechanism. These studies expand our understanding of the Pdu MCP， which has been linked to enteric pathogenesis and which provides a possible basis for the development of intracellular bioreactors for use in biotechnology.
