Franziska Kuhnert - AG Weber

 

Photosynthetic organisms, such as plants, algae and cyanobacteria, gain their energy by fixing CO2 to ribulose-1,5-bisphosphate, forming 3-phosphoglyerate. This step is catalyzed by Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Additional, RuBisCO is able to fix O2 forming the toxic intermediate 2-phosphoglycolate that has to be recycled in a process called photorespiration. While the soluble enzymes and metabolites of the photorespiratory pathway are well described, little is known about the transport proteins catalyzing the shuttling of metabolites between chloroplast, peroxisomes and mitochondria.

In total, at least 9 transport processes are necessary for the core photorespiratory pathway plus additional 11 transport reactions for photorespiration-associated processes. Furthermore, many enzymes of the pathway require specific coenzymes for their catalytic activities. Thus, additional transporters might be necessary to provide sufficient amounts of cofactors or their respective precursors. So far only the plastidic glycolate glycerate transporter (PLGG1) and the plastidial dicarboxylate transporter DIT1 and DIT2 have been characterized.

Recently, we have described the mitochondrial carrier A BOUT DE SOUFFLE from Arabidopsis thaliana (BOU) as a translocator involved in photorespiration. Though its function is clearly linked to the activity of the glycine decarboxylase, its substrate has not been identified so far. An analysis of the subunits of the glycine decarboxylase revealed that the P-protein is affected by the loss of BOU. Since the activity of the P-protein is dependent on pyridoxal 5’-phosphate, we hypothesize that BOU functions as a mitochondrial vitamin B6 transporter in Arabidopsis thaliana. During my PhD I want to unravel the molecular function of BOU. Therefore, I will quantify vitamer levels and activities of pyridoxal 5’-phosphate-dependent enzymes in isolated mitochondria.

 

Starting date: 23.03.2015 / PhD student

Thesis committee members: Andreas Weber, Peter Westhoff, Petra Bauer

Mini Academic CV:

    • 2015: Master of Science in Biochemistry, Heinrich Heine University Düsseldorf
      • Thesis: “Analysis of proton-coupled transport proteins" (Department of Plant Biochemistry
    • 2012: Bachelor of Science in  Biowissenschaften, University of Potsdam
      • Thesis: “Untersuchungen der Oberflächeneigenschaften von transitorischer Stärke aus der GWD-defizienten A. thaliana Mutante sex1-8" (Department of Plant Physiology)
Photo of Franziska  Kuhnert

Franziska Kuhnert M.Sc.

Building: 26.03
Floor/Room: 01.29
Phone +49 211 81-10474
Responsible for the content: E-MailDr. Petra Fackendahl