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Folgosa F, Camacho I, Penas D, Guilherme M, Fróis J, Ribeiro PA, Tavares P, Pereira AS. UV radiation effects on a DNA repair enzyme: conversion of a [4Fe-4S](2+) cluster into a [2Fe-2S] (2+). RADIATION AND ENVIRONMENTAL BIOPHYSICS 2015; 54:111-121. [PMID: 25249071 DOI: 10.1007/s00411-014-0569-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 09/17/2014] [Indexed: 06/03/2023]
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.
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Affiliation(s)
- Filipe Folgosa
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
- CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Inês Camacho
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Daniela Penas
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Márcia Guilherme
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - João Fróis
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Paulo A Ribeiro
- CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Pedro Tavares
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Alice S Pereira
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
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