UV radiation effects on a DNA repair enzyme: conversion of a [4Fe–4S]2+ cluster into a [2Fe–2S]2+

Abstract

Organisms are often exposed to different types of ionizing radiation that, directly or not, will promote damage to DNA molecules and/or other cellular structures. Because of that, organisms developed a wide range of response mechanisms to deal with these threats. Endonuclease III is one of the enzymes responsible to detect and repair oxidized pyrimidine base lesions. However, the effect of radiation on the structure/function of these enzymes is not clear yet. Here, we demonstrate the effect of UV-C radiation on E. coli endonuclease III through several techniques, namely UV-visible, fluorescence and Mössbauer spectroscopies, as well as SDS-PAGE and electrophoretic mobility shift assay. We demonstrate that irradiation with a UV-C source has dramatic consequences on the absorption, fluorescence, structure and functionality of the protein, affecting its [4Fe-4S] cluster and its DNA-binding ability, which results in its inactivation. An UV-C radiation-induced conversion of the [4Fe-4S](2+) into a [2Fe-2S](2+) was observed for the first time and proven by Mössbauer and UV-visible analysis. This work also shows that the DNA-binding capability of endonuclease III is highly dependent of the nuclearity of the endogenous iron-sulfur cluster. Thus, from our point of view, in a cellular context, these results strengthen the argument that cellular sensitivity to radiation can also be due to loss of radiation-induced damage repair ability.

[Fe–S] cluster assembly in the apicoplast and its indispensability in mosquito stages of the malaria parasite

“…However, an important SUF target protein ferredoxin (Fd), that functions as the major apicoplast redox system in conjunction with ferredoxin‐NADP+ reductase (FNR) contains [2Fe–2S] clusters . Oxidative and UV radiation‐mediated conversion of [4Fe–4S] clusters to [2Fe–2S] forms has been reported and it is possible that oxidizing agents such as H 2 O 2 and lipoate possibly present in the apicoplast contribute to conversion of [4Fe–4S] Fd to [2Fe–2S] Fd.…”

Iron management and production of electricity by microorganisms

“…As a functional component of heme groups, it participates in oxygen transport by hemoglobin, drug detoxification by cytochrome P450, or peroxides elimination by cytochrome c peroxidases (Atack and Kelly 2007;Behrendorff et al 2015;Pettigrew et al 2006;Poulos 1995). It also plays an important role as part of iron-sulfur cluster proteins, mediating mitochondrial electron transfer with the production of ATP (Vashchenko and MacGillivray 2013) or in DNA repair systems (Benjdia 2012;Folgosa et al 2015). It forms the binuclear site in ribonucleotide reductase, fundamental in the synthesis of DNA (Guarino et al 2014;Tomter et al 2013), among others.…”

UV Sensitivity of Free and Immobilized on Chitosan Matrix Proteases

“…These amino acids and cystine are responsible for the functional activity of the absorption of light quanta by protein macromolecules. This is evidenced by the coincidence of the spectra of proteins action photoinactivating with their absorption spectra [1][2][3][4].…”

“…UV rays have a high biological activity, they are extremely diverse applications in medicine, industry, agriculture. In connection with this work, which aimed at studying the biological effect of ultraviolet light on the study of UV-induced changes in the structural and functional characteristics of enzymes, remain relevant [1,3].…”