Department of Biotechnology, University of Mumbai, Vidyanagari Campus, Kalina, Santacruz (E), Mumbai 400098, India.
Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
Gene. 2021 Feb 5;768:145297. doi: 10.1016/j.gene.2020.145297. Epub 2020 Nov 9.
Escherichia coli exposed to 1-3 mM hydrogen peroxide undergo killing which is designated as the mode-one killing which is a result of oxidative DNA damage. Oxidative stress mediated DNA damage can be repaired by various DNA repair pathways like base excision repair, nucleotide excision repair and homologous recombination repair. In this study we have investigated the role of multiple DNA repair pathways in survival to oxidative killing and assessed their relative importance. Results show that both nucleotide excision repair pathway as well as the RecF pathway of recombination repair are important for repair of the DNA damage caused by exposure to hydrogen peroxide. The study also provides the evidence that RecG helicase which is known for the resolution of Holliday junction intermediates plays a critical role in the survival of mode-one killing by peroxide. There is a severe impact on the survival of repair mutants when parameters like aeration and growth medium are changed. Low aeration and growth in minimal medium provide significant protection from the mode-one killing suggesting that under natural conditions Escherichia coli cells are likely to be protected from the oxidative stress mediated DNA damage.
大肠杆菌暴露于 1-3mM 过氧化氢中会经历杀菌作用，这种杀菌作用被称为模式一杀菌，是氧化 DNA 损伤的结果。氧化应激介导的 DNA 损伤可以通过各种 DNA 修复途径（如碱基切除修复、核苷酸切除修复和同源重组修复）进行修复。在这项研究中，我们研究了多种 DNA 修复途径在氧化杀伤中的生存作用，并评估了它们的相对重要性。结果表明，核苷酸切除修复途径和重组修复的 RecF 途径都对修复过氧化氢暴露引起的 DNA 损伤很重要。该研究还提供了证据表明，RecG 解旋酶在解决 Holliday 连接中间体方面很有名，它在过氧化物模式一杀伤的存活中起着关键作用。当改变通气和生长培养基等参数时，修复突变体的存活受到严重影响。低通气和在最小培养基中生长为修复突变体提供了从模式一杀伤中显著的保护，这表明在自然条件下，大肠杆菌细胞可能受到氧化应激介导的 DNA 损伤的保护。
