PHD theses : Science
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Item structural &spectroscopic stuoies on antenna protein complexes sing atomic force &laser scanning microscop(ALNEELAIN UNIVERSITY, 2003) Elsiddiq Tawer Kafi AburassABSTRACT ln this work we studied mainly the structure and liunctionality of aggregated antenna molecules of photosynthetic purple bacteria. Our goal was to understand some of thc nicchtinism ul'solar Hltllilllflll cimvcisiuii in the hiulugical systciils. lllc iicccssity ol'l|tc work arises from the vital importance of the photosynthetic phenomena for lite on the earth to occur and continue, and the essential role which the antenna complexes play in this process. State-of the-art technology in the tield of microscopy was used for this goal. Atomic force and laser scanning microscopes were used as main tools in this work. Methods for crystallizing the LH2 protein complex were developed, and the ring structure olithis antenna complex was resolved to nano-metcr scale. lilectric conductivity ot' the Lll2 was studied with Scanning Tunneling Spectroscopy (STS). With One-Photon Excitation (OPE) technique the dipole strength of the energy transfer between adjacent Ll'l2’s in the inter-molecular spaces was postulated, and the kinetics ofthe energy was modeled in the intra-molecular spaces for the B850 group. A model suggesting the existence of a metastable state, and traps of excitations within the system is postulated. Two-l’l1oton Excitation (TPE) technique was successfully applied to chloroplasts. The 3D structure ofsingle intact chloroplast complexes was obtainable with good contrast. m