Description of Research Expertise

Dynamics and function of bioenergetic pathways in oxygenic chloroplast photosynthesis.

Our research is aimed to understand molecular mechanisms which are involved in assembly, function, maintenance and regulation of the photosynthetic machinery in oxygenic chloroplast photosynthesis. For this purpose, we are using the green alga Chlamydomonas reinhardtii as a primary model system and combining molecular techniques like reverse genetics and proteomics to elucidate these processes. Hereby, we are engaged in different research lines. We are currently investigating the adaptation and remodeling of the photosynthetic apparatus as a response to iron-deficiency. We are also interested in an understanding of chloroplast iron-homeostasis as a whole. The long term goal here is to discover the signaling pathway, from the sensing mechanism to the target genes and proteins that determines the operation of the photosynthetic apparatus as a function of iron nutrition. In another research line we are aiming to explore electron transfer and binding mechanisms between the soluble electron transfer proteins plastocyanin or cytochrome c6 and photosystem I (PSI). Additionally we aim to explore the molecular recognition between PSI and its light-harvesting protein complex (LHCI), allowing the formation of the PSI/LHCI complex, subunit remodeling as well as efficient excitation energy transfer. In a third research line we are currently establishing the basis for further systems approaches. Herein we are establishing two-dimensional protein maps of the thylakoid membrane proteome from wild type and mutant strains as well as new software tools to search the Chlamydomonas genomic database using mass spectrometric data. For proteomic analyses the laboratory is equipped with an ion-trap mass spectrometer (LCQ Deca XP plus, Thermo Finnigan) that is coupled to a UltiMate Nano liquid chromatography system (LC-Packings), containing a Switchos mirco column switching unit, a FAMOS autosampler and an UliMate Nano HPLC.