New insights into pterin‐photosensitized oxidation of 2′‐deoxyadenosine 5′‐monophosphate

Abstract

DNA and its components, the nucleotides, are susceptible to oxidation, whichalters normal cellular development and functioning, including the formation ofmutations and the appearance of cancerous processes. Therefore, the study of themechanisms involved in the oxidation of these molecules is relevant to preventdamage to genetic material. Electromagnetic radiation causes damage to DNAtriggering the oxidation of all nucleobases, with guanine being the most affected.Depending on the wavelength, UV radiation can cause direct or photosensitizeddamage to DNA and its components; however, since solar radiation has wave-lengths greater than 300 nm and is not absorbed by nucleobases, the primarydamage is photosensitized. Here, we are presenting new evidence on the photosen-sitized oxidation of the adenine nucleotide, 2′-deoxyadenosine 5′-monophosphate(dAMP). Pterin is used as a model photosensitizer since it is present in all livingsystems and absorbs radiation in the UV-A region, the main UV component insolar radiation. We analyze the mechanisms involved and the role of superoxideanion (O2•−), evidencing that this reactive oxygen species protects dAMP by re-covering the nucleotide after one-electron oxidation. Oxidation product analysisrevealed the formation of 2′-allantoin-5´monophosphate (dAlMP).