title: The N-terminal region of the medium subunit (PduD) packages adenosylcobalamin-dependent diol dehydratase (PduCDE) into the Pdu microcompartment.
abstract: Salmonella enterica produces a proteinaceous microcompartment for B(12)-dependent 1,2-propanediol utilization (Pdu MCP). The Pdu MCP consists of catabolic enzymes encased within a protein shell, and its function is to sequester propionaldehyde, a toxic intermediate of 1,2-propanediol degradation. We report here that a short N-terminal region of the medium subunit (PduD) is required for packaging the coenzyme B(12)-dependent diol dehydratase (PduCDE) into the lumen of the Pdu MCP. Analysis of soluble cell extracts and purified MCPs by Western blotting showed that the PduD subunit mediated packaging of itself and other subunits of diol dehydratase (PduC and PduE) into the Pdu MCP. Deletion of 35 amino acids from the N terminus of PduD significantly impaired the packaging of PduCDE with minimal effects on its enzyme activity. Western blotting showed that fusing the 18 N-terminal amino acids of PduD to green fluorescent protein or glutathione S-transferase resulted in the association of these fusion proteins with the MCP. Immunoprecipitation tests indicated that the fusion proteins were encapsulated inside the MCP shell.
authors.affiliation: Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Chenguang
authors.initials: C
authors.lastname: Fan
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Bobik
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003038:Cobamides / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D011408:Propanediol Dehydratase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019946:Propylene Glycol / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019779:Salmonella enterica / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D003038:Cobamides; D021122:Protein Subunits; D019946:Propylene Glycol; D011408:Propanediol Dehydratase; C000913:cobamamide