Design of nucleolytic synzymes and their interactions with nucleic acids

SUMMARY Desing of Nucleolytic Synzymes and Their Interactions with Nucleic Acids In this study, nucleolytic capabilities of the complexes of a novel oxime-type ligand, homodinuclear copper (Kl), heterodinuclear copper-manganese (K2) and homotrinuclear copper (K3) complexes were investigated by neutral agarose gel electrophoresis and visible spectrophotometry. All the complexes in the absence of MMPP had no nucleolytic activity on the pCYTEXP. Therefore, it is obvious that the observed nucleolytic activities in the presence of MMPP were originated from the nature of the complexes. Kl and K2 especially at below 0. 1 uM nick the supercoiled DNA however at their greater concentrations linear forms were dominant. K3, however, has shown such nucleolytic activity at approximately 100 uM indicating that its activity is weaker than the other two complexes. At efficient concentrations of the complexes, within the first 5 minutes of reaction period all the supercoiled form transformed to the nicked form and then linear forms were formed. These results show that all of the complexes perform their nucleolytic activities by similar mechanisms. Kl and K2 have also shown very similar pH- dependent nucleolytic profiles but different than K3. The nucleolytic efficiencies of the examined complexes on the pCYTEXP DNA were also investigated by spectroscopy. Absorbance changes and very small shifts of some specific signals on the visible spectra of all the complexes indicate a weak possibility of intercalation with the DNA. It can be concluded by taking the chemical structures of the complexes into consideration that the complexes Kl and K2 possess potential nucleolytic efficiences by similar mechanisms. The results obtained in this preliminary study should give new ideas on the molecular design of DNA cleaving molecules and anticancer agents having oxime functionalities. Key Words: Oxime, Nucleic Acid, Copper(II), Supercoiled DNA, Nuclease VI