Metal containing complexes such as Fe-EDTA have been shown to be excellent DNA cleaving agents. For the purposes of this project, the activity and mechanism of DNA cleavage by Cobalt containing complexes, such as Co-Bcyclam, Co-Bcyclen, Co-Bn<sub>2</sub>cyclam, and Co-Bn<sub>2</sub>cyclen were explored. In DNA cleavage assays employing pUC19 as the substrate, all of these complexes exhibited the ability to cleave phosphodiester bonds in the pUC19 DNA backbone. In addition, the mechanism of hydrolysis of these metals was tested by measuring DNA cleavage in the presence and absence of hydrogen peroxide. All four Cobalt complexes were shown to operate using both expected mechanisms: an oxidative and hydrolytic mechanism. This makes these molecules excellent candidates for use as cleavage agents in synthetic nucleases. Custom made synthetic nucleases that specifically target specific DNA sequences and hydrolyze a specific bond could revolutionize the genetic engineering and gene therapy industries. The ability of the potential cleavage agent to operate via hydrolytic mechanism is imperative as it does not depend on the introduction of free radicals which could harm a biological system. The different ligands associated with these four cobalt complexes appear to have similar reaction rates but it is currently unknown how sequence specific they are individually. Future work includes investigating sequence specificity of each complex by running DNA cleavage reactions with varied DNA sequences as substrates and comparing different kinetic parameters. If these molecules are shown to be nonspecific cleavage agents, a specific targeting sequence can be added to the metal complex as a DNA binding domain to make the nuclease more specific. If these molecules do show affinity for specific DNA sequences, the ligands can then be compared and potentially altered to attack desired sequences.

Investigation of the activity and mechanism of DNA cleavage by cobalt-cyclen and -cyclam complexes

251st National Meeting (2016)

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