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Construction of a chassis and synthetic modules for H 2 production (BioModularH 2 ) Catarina Pacheco Cellular and Applied Microbiology Group IBMC, INEB S12. Biologia de Sistemas Encontro com a Ciência e Tecnologia em Portugal Centro de Congressos de Lisboa,7 th July 2010
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Synthetic Biology is...... the design and construction of new biological parts, devices and systems and the re-design of existing, natural biological systems for useful purposes. Synthetic Biology is the application of engineering concepts to biology
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Standardizedparts Assembly of modules and circuits Incorporation in a chassis
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Consortium members: Instituto de Biologia Molecular e Celular (Portugal) École Polytechnique (France) Universidad Politécnica de Valencia (Spain) Uppsala Universitet (Sweden) University of Sheffield (UK) Weizmann Institute of Science (Israel) FP6-2005-NEST-PATH Contract no.: 043340 Jan.07- Jul.10
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In silico analysis Computational design of parts and modules Synthesis of parts Assembly of modules Preparation of the chassis Characterization of parts/modules Incorporation in the chassis Evaluation of the final product BioModularH 2 Design Construction Characterization
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Final goal A cyanobacterial chassis that together with the designed devices will harvest solar energy for H 2 production. The synthetic parts and modules will be available for other biotechnological applications
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Photoautotrophic chassis - Photoautotrophic chassis - Synechocystis sp. PCC 6803 the most studied cyanobacteria unicellular and non-N 2 -fixing simple nutritional requirements naturally transformable molecular tools for manipulation available small genome comprising a 3.6 Mb genome and 7 plasmids (1 st cyano genome sequenced)
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Preparation of the chassis Tuning respiration Native hydrogenase (s) Nuclease(s) etc… Oxygen consumption Oxygen sensing Highly-efficient O 2 -tolerant hydrogenase Reduce constraints, e.g. enhance transformation efficiency Remove redundant genes / parts Minimize O 2 production / maximize O 2 consumption H 2 ases are very sensitive to O 2
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Deletion of redundant parts – generation of a hydrogenase deficient mutant Possesses hoxYH Sensitive to kanamycin Resistant to sucrose hoxYhoxH Deletion of hoxYH Resistant to kanamycin Sensitive to sucrose Lacks hoxYH Sensitive to kanamycin Resistant to sucrose
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Identification of neutral sites for the insertion of synthetic modules Genes encoding proteins: - unknown or hypothetical - with maximum length of 300 a.a. - without predicted transmembrane domains (TMHMM Server v. 2.0) - primary or secondary structure without relevant homologues - that do not interact with other proteins in two-hybrid system (CyanoBase data) 16 potential neutral sites identified
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- RT-PCRs were performed using total RNA collected from Synechocystis sp. PCC 6803 cultures in the exponential phase (OD 730 = 0.8). 6 neutral sites selected for the generation of mts Transcription assessment by RT-PCR
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HydA1_Fd Construction of synthetic devices - Hydrogen Producing Device (HPD) Homology models based on Chang et al. 2007 (Biophys J, 93:3034-45) Hydrogenase module Fe-only hydrogenase fused to ferredoxin – Chlamydomonas reinhardtii Maturation module HydEF + HydG – Chlamydomonas reinhardtii
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The OCD will create the intracellular microaerobic environment necessary for optimal hydrogenase activity. Construction of synthetic devices – Oxygen Consuming Device (OCD) Hydrogenase OCD High O 2 pressure Low O 2 pressure O 2 Sensor H2H2 H2H2 H2H2 H2H2 H2H2 H2H2
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- A-type flavoprotein (ATF) – Synechocystis sp. PCC 6803 - Laccase – Escherichia coli SINGLE-protein modules O 2 H 2 O TWO-protein module O 2 H 2 O 2 ½ O 2 + H 2 O - Glucose oxidase – Penicillium amagasakiense + Catalase – Synechocystis sp. PCC 6803 Construction of synthetic devices – Oxygen Consuming Device (OCD)
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Characterization of synthetic devices – Laccase device characterization (E. coli) M9 Glycerol medium vs. M9 Glycerol medium Cu supplemented induction: - stationary growth phase cell harvest: - 12/24 hours after induction. Lac (56 kDa) MW 97 kDa 66 kDa 45 kDa 30 kDa 20 kDa - - + - + - + - + AHL 12h 24h12h 24h - - - - - + + + + Cu(II) F2026 + laccase 24h wt SDS-PAGE
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Spectrophotometric assay ( ABTS oxidation) - Specific laccase activity was expressed as units of activity per µg of protein extract, where 1 activity unit represents 1 µmol of ABTS oxidized per min. Characterization of synthetic devices – Laccase device characterization (E. coli) O 2 consumption (Clark-type O 2 electrode) - Oxygen consumption was expressed as nmol O 2 consumed per min and normalized per µg of protein extract.
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Ongoing Work: Oxygen Consuming Device Chassis Synechocystis sp. PCC 6803 Oxygen Consuming Device Highly-efficient O 2 -tolerant hydrogenase Chassis with Hydrogen Producing Device (Syn. 6803)
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Cellular and Applied Microbiolgy group BioModularH 2 team - Paula Tamagnini - Catarina Pacheco - Filipe Pinto - Miguel Lopo - Sérgio Ferreira - Zsófia Büttel - Meritxell Llorens SFRH / BPD / 64095 / 2009 (Catarina Pacheco) SFRH/BD/36378/2007 (Filipe Pinto)
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