Presentation Title

Inhibition of Oxidative DNA-protein Cross-linking Via Aqueous Extract of Kale

Faculty Mentor

Eric Stemp

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 20

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Oxidative damage is involved in the formation of free radicals, which can cause various diseases ranging from Alzheimer’s disease to cancer. One form of oxidative damage is DNA-protein cross-linking where proteins interact with lesions in the DNA. In DNA, this damage is observed primarily at guanine (G) because it is the most easily oxidized base. Therefore, we examined whether kale can inhibit oxidative DNA damage by using the flash-quench scheme. The flash-quench technique is a method used for guanine oxidation and can induce DNA-protein cross-linking. In the flash quench technique, the intercalator, Ru(phen)2dppz2+[phen = phenanthroline, dppz = dipyridophenazine], is excited with a laser and gives an electron to the quencher, Co(NH3)5Cl2+. The intercalator takes an electron from guanine, creating the guanine radical, which then reacts with protein. In our experiment, samples containing Ru(phen)2dppz2+, Co(NH3)5Cl2+, histone protein, calf thymus (pUC19) DNA and an aqueous extract of kale were irradiated with blue laser light for 0 to 120 seconds to induce guanine damage. The extent of cross-linking was determined by the gel shift assay where SDS was added to the samples to disrupt the noncovalent interactions between the DNA and the protein. Furthermore, the samples were compared with the control which substituted water for kale extract. Upon comparison, minimal DNA protein cross-linking was observed when kale was present in the samples. Our results showed that as the irradiation time increased, the absorption of free DNA was lowered. The inhibition of oxidative DNA damage by kale was studied further by focusing on kaempferol, a component of kale. Likewise, the gel shift assay was performed on samples containing water and 200 µM kaempferol. Since kaempferol holds known antioxidative properties, the inhibition of DNA oxidation at the guanine site was expected. In future work, the use of emission spectroscopy will determine how the kaempferol affects the quenching process and how the antioxidants react directly with the guanine radical.

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Inhibition of Oxidative DNA-protein Cross-linking Via Aqueous Extract of Kale

CREVELING 20

Oxidative damage is involved in the formation of free radicals, which can cause various diseases ranging from Alzheimer’s disease to cancer. One form of oxidative damage is DNA-protein cross-linking where proteins interact with lesions in the DNA. In DNA, this damage is observed primarily at guanine (G) because it is the most easily oxidized base. Therefore, we examined whether kale can inhibit oxidative DNA damage by using the flash-quench scheme. The flash-quench technique is a method used for guanine oxidation and can induce DNA-protein cross-linking. In the flash quench technique, the intercalator, Ru(phen)2dppz2+[phen = phenanthroline, dppz = dipyridophenazine], is excited with a laser and gives an electron to the quencher, Co(NH3)5Cl2+. The intercalator takes an electron from guanine, creating the guanine radical, which then reacts with protein. In our experiment, samples containing Ru(phen)2dppz2+, Co(NH3)5Cl2+, histone protein, calf thymus (pUC19) DNA and an aqueous extract of kale were irradiated with blue laser light for 0 to 120 seconds to induce guanine damage. The extent of cross-linking was determined by the gel shift assay where SDS was added to the samples to disrupt the noncovalent interactions between the DNA and the protein. Furthermore, the samples were compared with the control which substituted water for kale extract. Upon comparison, minimal DNA protein cross-linking was observed when kale was present in the samples. Our results showed that as the irradiation time increased, the absorption of free DNA was lowered. The inhibition of oxidative DNA damage by kale was studied further by focusing on kaempferol, a component of kale. Likewise, the gel shift assay was performed on samples containing water and 200 µM kaempferol. Since kaempferol holds known antioxidative properties, the inhibition of DNA oxidation at the guanine site was expected. In future work, the use of emission spectroscopy will determine how the kaempferol affects the quenching process and how the antioxidants react directly with the guanine radical.