témavezető: Zimányi László
helyszín (magyar oldal): MTA Szegedi Biológiai Kutatóközpont helyszín rövidítés: SZBK
A kutatási téma leírása:
Biological energy transformation is based on the migration of electrons through well organized protein chains towards lower energy. There is, however, a basic difference between the mechanism of electronic conductance in a metal wire and in a protein. In proteins, electron conductance is accomplished via quantum mechanical tunneling, which strongly depends on the intervening medium between electron donor and acceptor. Our goal is to better understand the mechanism of electronic conductance in proteins, and to study whether or not nature has optimized (and how) the conductance in certain important proteins. One of our proteins of choice is cytochrome c, the soluble, mobile electron carrier connecting complexes III and IV in mitochondria. We investigate intraprotein and interprotein electron transfer initiated by a covalent photoactive redox label attached to the protein surface. We study the effect of the structure and dynamics of the protein matrix on the rate of electron transfer. By producing mutants we map the electron transfer efficiency of the different regions of the protein. The other protein of choice is the membrane protein cytochrome b561, with two heme b redox centers presumably participating in transmembrane electron transfer. Kinetic spectroscopic experiments to determine the electron transfer rate and efficiency are supported by molecular modelling and electron transfer pathway calculations. Cytochromes are promising candidates as components of biomolecule-based sensors, bioelectronic designs, so the understanding of their electric conductance is a high priority. Within the framework of international collaborations we also plan to incorporate cytochrome c into hybrid biophotonic architectures – photonic crystals based on porous silicon. Thereby we expect to tune the optical properties of the semiconductor-based photonic crystals using the colored cytochrome protein. Conversely, we intend to study the effects of the interesting nonlinear optical phenomena characteristic of the photonic crystals on the optical properties of the protein.
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