Vous êtes ici : Accueil > Towards Assembly of a Type I Reaction Center in a Purple Phototroph


Séminaire invité

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

Du 06/09/2017 au 06/09/2017
 Marcia Ortega Ramos (The Pennsylvania State University)

Conférencier : Marcia Ortega Ramos (The Pennsylvania State University) invitée par G. Peltier (SBVME/LB3M)

Résumé :
Marcia Ortega Ramos, Daniel P. Canniffe, Matt Radle, Donald A. Bryant and John Golbeck
Dept. of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802 

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. 

Infos Pratiques

Salle de conférence du bâtiment 177, de 11h00 à 12h00, Centre CEA Cadarache
Pour les extérieurs, merci de contacter Najat Comte au 04 42 25 27 53 pour les formalités d'entrée sur le centre.

Haut de page