Presentation Title

Oxidative DNA Damage Prevention via Tyrosine and Tryptophan in a Peptide Model System

Faculty Mentor

Dr. Eric Stemp

Start Date

17-11-2018 8:15 AM

End Date

17-11-2018 8:30 AM

Location

C301

Session

Oral 1

Type of Presentation

Oral Talk

Subject Area

health_nutrition_clinical_science

Abstract

The low oxidation potential of guanine allows for it to be the most common site of oxidative damage. This oxidation was effected in our experiments by the flash-quench technique, a method that can induce DNA-protein crosslinking. 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. Although permanent damage such as protein crosslinks can be formed, the electron deficiency in guanine can be filled via electron donor to prevent such formations. Among the many antioxidants present in vivo are those based upon tyrosine or tryptophan. Here, we used a peptide model system to investigate which antioxidant class, tyrosine-based or tryptophan based, is better at preventing oxidative DNA damage. The peptide design used in these experiments is Ac-(Ala)2R(Ala)2R(Ala)3X(Ala)3R(Ala)2R(Ala)2-NH2.

Summary of research results to be presented

Peptides designed to contain tyrosine and tryptophan have shown to prevent the formation of DNA adducts by acting as an electron donor to the guanine radical.

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Nov 17th, 8:15 AM Nov 17th, 8:30 AM

Oxidative DNA Damage Prevention via Tyrosine and Tryptophan in a Peptide Model System

C301

The low oxidation potential of guanine allows for it to be the most common site of oxidative damage. This oxidation was effected in our experiments by the flash-quench technique, a method that can induce DNA-protein crosslinking. 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. Although permanent damage such as protein crosslinks can be formed, the electron deficiency in guanine can be filled via electron donor to prevent such formations. Among the many antioxidants present in vivo are those based upon tyrosine or tryptophan. Here, we used a peptide model system to investigate which antioxidant class, tyrosine-based or tryptophan based, is better at preventing oxidative DNA damage. The peptide design used in these experiments is Ac-(Ala)2R(Ala)2R(Ala)3X(Ala)3R(Ala)2R(Ala)2-NH2.