Development of Detection Methods of Dynamical Higher Order Structures of Proteins and Its Application to Elucidation of Structure-Function Relations of Proteins.

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Structural biology became a main subject in biophysical chemistry after the human genome problem, and 'Protein 3000' project has been successfully carried out. This project intended to uncover the protein structures with x-ray crystallography and NMR spectroscopy. Thus, the static structures of many proteins have been solved, but dynamical structures remained to be revealed to understand how proteins perform their functions. Our research aimed to provide more detailed structures of active sites of large proteins and also dynamical structures in their functioning state. For this purpose vibrational spectroscopy was adopted. New systems for obtaining time-resolved visible and ultraviolet resonance Raman spectra and microscope FTIR spectra were developed and applied to the following eights subjects; 1) Detection of ultrafast structural change of chromophores by using picosecond time-resolved visible resonance Raman spectroscopy, 2) Detection of fast changes of higher order structures of p … More roteins by using subnanosecond time-resolved ultraviolet resonance Raman spectroscopy, 3) Elucidation of the primary process in protein folding/unfolding by using laser temperature jump technique, 4) Development of a novel spectroscopy for functionally-important protein fluctuation, 5) Elucidation of the primary process in the light-induced DNA repair by DNA photolyases, 6) FTIR microspectroscopic investigation of amyloid fibril structures and a trigger mechanism along its formation, 7) Mechanism of sensing of environment and information transduction to a functional domain by gas sensor heme proteins, 8) Elucidation of mechanism of oxygen activation and proton active transport by heme enzymes. In practice we have constructed several inventive time-resolved resonance Raman systems, which cover a wide ranges of excitation wavelengths (from ultraviolet to near infrared) and time-resolution (from picosecond to second). We applied these systems successfully to basic proteins like hemoglobin and myoglobin and some new proteins like gas sensor proteins. We succeeded in elucidating mechanisms of target discrimination and information transmission in the gas sensor proteins. Less