Henrike Niederholtmeyer

Publications (3)17.46 Total impact

• Source

  Available from: Patricia Grob

  Article: Modularity of a carbon-fixing protein organelle.

  Walter Bonacci, Poh K Teng, Bruno Afonso, Henrike Niederholtmeyer, Patricia Grob, Pamela A Silver, David F Savage
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  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.
  Proceedings of the National Academy of Sciences 12/2011; 109(2):478-83. · 9.68 Impact Factor
• Source

  Available from: PubMed Central

  Article: Towards a synthetic chloroplast.

  Christina M Agapakis, Henrike Niederholtmeyer, Ramil R Noche, Tami D Lieberman, Sean G Megason, Jeffrey C Way, Pamela A Silver
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  ABSTRACT: The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner. We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages. Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices.
  PLoS ONE 01/2011; 6(4):e18877. · 4.09 Impact Factor
• Article: Engineering cyanobacteria to synthesize and export hydrophilic products.

  Henrike Niederholtmeyer, Bernd T Wolfstädter, David F Savage, Pamela A Silver, Jeffrey C Way
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  ABSTRACT: Metabolic engineering of cyanobacteria has the advantage that sunlight and CO(2) are the sole source of energy and carbon for these organisms. However, as photoautotrophs, cyanobacteria generally lack transporters to move hydrophilic primary metabolites across membranes. To address whether cyanobacteria could be engineered to produce and secrete organic primary metabolites, Synechococcus elongatus PCC7942 was engineered to express genes encoding an invertase and a glucose facilitator, which mediated secretion of glucose and fructose. Similarly, expression of lactate dehydrogenase- and lactate transporter-encoding genes allowed lactate accumulation in the extracellular medium. Expression of the relevant transporter was essential for secretion. Production of these molecules was further improved by expression of additional heterologous enzymes. Sugars secreted by the engineered cyanobacteria could be used to support Escherichia coli growth in the absence of additional nutrient sources. These results indicate that cyanobacteria can be engineered to produce and secrete high-value hydrophilic products.
  Applied and environmental microbiology 04/2010; 76(11):3462-6. · 3.69 Impact Factor