MOLECULAR, SUBCELLULAR AND MICROBIAL BIOPHYSICS
László ZIMÁNYI - head of research unit, scientific adviser
Tibor PÁLI - head of research group, scientific adviser
Gábor RÁKHELY - head of research group, senior research associate
MOLECULAR, SUBCELLULAR AND MICROBIAL BIOPHYSICS
A fascinating complexity at different levels of organization from individual protein molecules through subcellular organelles (e.g. membrane systems) to whole cells hides behind the multitude, variety and efficiency of processes common to living organisms. Subatomic and atomic events, such as electron transfer, ion transport, forming and breaking of chemical bonds or other, weaker (but equally important) interactions, electronic interaction with light and energy conversion, mechanical motion, etc. are studied in the Molecular, subcellular and microbial biophysics research unit using a wide arsenal of biophysical techniques combined with molecular biology, site directed mutagenesis as well as theoretical modeling. Interactions between proteins, with emphasis on special autocatalytic reactions, interactions of polypeptides and proteins with lipid membranes and the spontaneous folding of proteins in the membrane are also addressed. Knowledge of the molecular events is utilized at the cellular level in practical applications such as bioremediation or biofuel production. The biological physics of certain proteins interfaced with special semiconductor photonic crystals is also investigated to pave the road for potential biophotonic and bioelectronic applications.
The kinetics and energetics of electron and ion transfer both in soluble and in membrane proteins has been and remains in the focus of the Protein biophysics research group. Based on the accumulated information on several redox and/or “colored” proteins they are also investigating the biophotonic and bioelectronic properties of these proteins when embedded in porous silicon photonic crystalline matrices. The family of the transmembrane, di-heme electron transporter cytochrome b561 proteins, with special emphasis on two putative tumor suppressor representatives is another major research interest in the group. With the aid of homology modeling based on the single available X-ray structure among these proteins, and in the absence of the knowledge of the physiological function in several cases, they carry out structural-functional investigations on wild type and site directed mutants of these membrane proteins for a better understanding of their significance. Following the discovery of the simplest autocatalytic reactions in biological material, localized within and outside of the enzymatic cycle of the Hyn hydrogenase from Thiocapsa roseopersicina, they continue to study its detailed mechanism. The significance is reaching beyond the mechanism of the splitting of hydrogen into proton and electron, as autocatalysis is a key component of e.g. the prion diseases.
In the Atomic Force Microscopy laboratory, in close collaboration with the Physiology and pathology of the blood-brain barrier research group, various physical (mechanical) properties of the endothelial cell layer, forming the wall of the cerebral microcapillaries, are studied. Atomic Force Microscopy enables the investigation of the plastic properties of cells, the measurement of the forces between them, identifying the factors determining their permeability, e.g. how the endothelial layer reacts to the invasion of metastatic cancerous cells.
The role of various hydrogenases as well as nitrogenases in microbial energetics, in hydrogen metabolism, their regulation, reaction mechanism and metabolic linkages are also part of the research interest of the Microbial biotechnology research group. Their activities also include the study of the metabolism of various microbes for potential biotechnological applications, such as the production of biofuels or the bioremediation of hazardous waste, utilizing either light energy or processes of dark fermentation, or the combination thereof. Their experimental approach ranges from chemical, microbial and metagenomic techniques to molecular biology, functional genomics and biophysics.
The main focus of the Membrane biophysics research group is concerned with the functional interaction of membrane proteins with the lipid components of the membrane, including the effects leading to the spontaneous protein folding into the membrane. In addition, they study the molecular mechanism behind the fascinating transmembrane molecular motor of the vacuolar proton-ATPase protein. They use a wide variety of spectroscopic and calorimetric methods, combined with theoretical modeling, to study the folding and membrane insertion of alfa helical or beta barrell proteins (protein segments). In modeling these processes they take into account the interactions of the polypeptide with the lipid as well as the solvent environment, while extracting parameters for the modeling from experimental data.