Ms. Mariana Grieben

Groth Group Biochemical Plant Physiology Heinrich Heine University Universitätsstr.1, Geb. 26.02.01 40225 Düsseldorf, Germany  +49(0)211-81-15232

Mini Academic CV

University degrees:

First degree or intermediate examination:

• BSc(Biochemistry), 2006, Heinrich-Heine University, Düsseldorf, Germany

Second degree and/or intermediate examination:

• MSc(Biochemistry), 2008, Heinrich-Heine University, Düsseldorf, Germany

Further degrees and/or interemediate examinations:

• Vordiplom(Landscape Ecology), 2004, Westfälische Wilhelms University, Münster, Germany

BioStruct PhD project

Structure and regulation of chloroplast F₀F₁ ATP synthase
F₀F₁-ATP synthases found in bacteria, mitochondria and in the photosynthetic membranes of chloroplasts or cyanobacteria catalyze the formation of ATP from ADP and inorganic phosphate at the expense of a transmembrane proton gradient. The F₀F₁ holoenzyme consists of the membrane-embedded F₀-domain and the interconnected soluble F₁-domain. The energy of the transmembrane proton gradient is used by F₀ to translocate protons, which is coupled to ATP synthesis via a rotary catalytic mechanism located on F₁. In contrast to bacterial and mitochondrial F-ATPases chloroplast F₁ is a latent ATPase requiring activation before catalytic turnover can take place. The activation is regulated via the redox state of two cysteines in the gamma-subunit. Detailed information on the molecular mechanism of this regulation is anticipated from high resolution structures of the oxidized and the reduced F₁-complex from the thermophilic cyanobacterium Thermosynechococcus elonagatus BP-1. The structural basis of the redox regulation of photosynthetic F ATPases will be further addressed by structural studies on the isolated, recombinant spinach chloroplast gamma-subunit. We intend to crystallize the isolated gamma-subunit in the reduced and oxidized form as well as a redox-complex of gamma with the natural redox-compound thioredoxin. The second main objective of the project is to solve the structure of the intact F0F1 holoenzyme. Previous structural studies on F₀F₁ have shown that the F₀-F₁ contact is fragile. In order to stabilize the F₀F₁ interaction we will construct chimeric enzymes containing the membrane embedded F₀ from Escherichia coli and the catalytic F₁ from Thermo synechococcus which are amenable to cysteine-crosslinking.

Topic Supervisor: Prof. Dr. Georg Groth, Institute for Biochemical Plant Physiology, Heinrich Heine University Duesseldorf, Groth Group

Complementary Supervisor: Prof. Lutz Schmitt, Institute for Biochemistry, Heinrich Heine University Duesseldorf, Schmitt Group

BioStruct Fellow: Ms. Mariana Grieben

Foto: Hanne Horn