Spectral Study On The Properties Of CopC

Copper is an essential trace element required for survival by all organisms from bacterial cells to humans. Copper ions undergo unique chemistry due to their ability to adopt distinct redox states, either oxidized [Cu(II)] or in the reduced state [Cu(I)], and they serve as important catalytic cofactors in redox chemistry for proteins that carry out fundamental biological functions that are required for growth and development. While copper is essential, it is also a potent cytotoxin when allowed to accumulate in excess of cellular needs. Cu is readily participates in reactions that result in the production of highly reactive oxygen species (ROS) including hydroxyl radical. Hydroxyl radicals are believed to be responsible for devastating cellular damage that includes lipid peroxidation in membranes, direct oxidation of proteins, and cleavage of DNA and RNA molecules. It is highly orchestrated that highly toxin and nutrition element copper was uptake and distribution in cells. Copper chaperones play an important role in the process of copper transportation and distribution in cells.CopC is one of four copper regular proteins in Pseudomonas Syringae pathovar tamato. In solution CopC adopts a fold essentially constituted by nine p-sheet forming a barrel motif which both N-terminal and C-terminal can bind to Cu(II) and Cu(I), respective. The two copper binding sites are about 30 A apart. All of these have been conformed by the method of nuclear magnetic resonance and extended X-ray absorption fine structure spectroscopy. Whether or not CopC could act on metallochaperone is not known now. In order to resolve this problem, the following work was done in this paper:1. Plenty of highly pure CopC was obtained by means of molecular biology and cation, anion chromatography . It was checked by SDS-PAGE, gel filtration, mass spectra and UV-absorption spectrum.2. The interactions between CopC and Cu(II), Hg(II), Ag(I) and so on wereinvestigated, Using fluorescence and UV-vis spectra. The results show that CopC could highly affinity bind to Cu(II).The fluorescence of CopC could not be quenched by Mn(II)> Co(II)> Fe(II)and Ni(II) which may be imply that CopC can't bind to them. The complex of Cun-CopC is more stable than ones of between CopC and Hg(II) or Ag(I).All these suggest that CopC could specially binding to Cu(II).3. The stable energy of CopC and Cun-CopC were calculated according to two states mechanism. The form of Cun-CopC is more stable. The distance between Cu(II) and tryptophan was also calculated in the light of Foster nonradiation energy transfer theory and it is about 11.6A.4. Using 4-(l-pyrenyl) butyroyl acid and pyridoxineas probes, the supper molecular property of CopC was studied. One or several small organic molecular could be bound by CopC, and the conditional constants are more than 104mol/L.