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12 September 2017: 2 events

  • Cytoskeleton club

    Tuesday 12 September 2017 11:30-12:30 - Christophe Le Clainche

    Cytoskeleton Club

    Résumé : Understanding cellular force response through the in vitro reconstitution of mechanosensitive protein machineries

    Lieu : Bibliothèque - Bâtiment 34, campus de Gif

    En savoir plus : Cytoskeleton club
  • Microbiology department

    Tuesday 12 September 2017 12:45-13:45 - Dr Marcia ORTEGA RAMOS - Dept. of Biochemistry & Molecular Biology, The Pennsylvania State University University Park, Etats-Unis

    Towards Assembly of a Type I Reaction Center in a Purple Phototroph

    Résumé : Engineering photosynthetic bacteria to utilize a heterologous reaction center (RC) containing a different photo-pigment could improve solar energy conversion efficiency by allowing the cell to absorb a broader range of the solar spectrum. One promising candidate is the homodimeric Type I RC from Heliobacterium modesticaldum (HbRC). It is the simplest known RC and has the benefit of using Bchl g, which absorbs in the near-infrared region of the spectrum. The purple phototrophic bacterium Rhodobacter (Rba.) sphaeroides was chosen as the platform into which the HbRC is introduced. However, to assemble a functional HbRC, engineered production of bacteriochlorophyll g (BChl g), must first be achieved. BChl g and BChl b are two chlorophyll (Chl) derivatives that contain an ethylidene substituent on ring B and share very similar biosynthetic pathways. Using the background strain Rba. sphaeroides producing BChl b rather than the native BChl a, we were able to re-direct the biosynthesis of pigments to produce an analog of BChl g. The majority of Chls and BChls found in nature contain a C20 phytyl alcohol moiety, whereas BChl g contains a shorter C15 farnesyl tail. To ensure that the BChl g produced in Rba. sphaeroides can be correctly incorporated into a heterologous HbRC, we are redirecting the native terpenoid pathway to produce these shorter alcohol moieties. By combining both strategies we may be able to generate a functional HbRC in Rba. sphaeroides. Ultimately this mutant will be used as the platform in which the HbRC will be assembled. This strategy could be applicable to other organisms, such as cyanobacteria, thereby expanding the range of the solar spectrum they are able to absorb.
    Invitée par l’équipe "Biologie et Biotechnologie des Cyanobactéries"

    Lieu : Salle Kalogeropoulos - Bâtiment 400, campus d’Orsay

    En savoir plus : Microbiology department