title: Modularity of a carbon-fixing protein organelle.
abstract: Bacterial microcompartments are proteinaceous complexes that catalyze metabolic pathways in a manner reminiscent of organelles. Although microcompartment structure is well understood, much less is known about their assembly and function in vivo. We show here that carboxysomes, CO(2)-fixing microcompartments encoded by 10 genes, can be heterologously produced in Escherichia coli. Expression of carboxysomes in E. coli resulted in the production of icosahedral complexes similar to those from the native host. In vivo, the complexes were capable of both assembling with carboxysomal proteins and fixing CO(2). Characterization of purified synthetic carboxysomes indicated that they were well formed in structure, contained the expected molecular components, and were capable of fixing CO(2) in vitro. In addition, we verify association of the postulated pore-forming protein CsoS1D with the carboxysome and show how it may modulate function. We have developed a genetic system capable of producing modular carbon-fixing microcompartments in a heterologous host. In doing so, we lay the groundwork for understanding these elaborate protein complexes and for the synthetic biological engineering of self-assembling molecular structures.
authors.affiliation: Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Walter
authors.initials: W
authors.lastname: Bonacci
authors.forename: Poh K
authors.initials: PK
authors.lastname: Teng
authors.forename: Bruno
authors.initials: B
authors.lastname: Afonso
authors.forename: Henrike
authors.initials: H
authors.lastname: Niederholtmeyer
authors.forename: Patricia
authors.initials: P
authors.lastname: Grob
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Silver
authors.forename: David F
authors.initials: DF
authors.lastname: Savage
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002451:Cell Compartmentation / Q000502:physiology*; D002498:Centrifugation; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D049452:Green Fluorescent Proteins; D044222:Halothiobacillus / Q000737:chemistry* / Q000378:metabolism; D046912:Multiprotein Complexes / Q000378:metabolism*; D018085:Regulon / Q000235:genetics*; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D046912:Multiprotein Complexes; D002245:Carbon Dioxide; D049452:Green Fluorescent Proteins; D012273:Ribulose-Bisphosphate Carboxylase