Lewinska Anna, Grzelak Agnieszka, Bartosz Grzegorz
Department of Biochemistry and Cell Biology, University of Rzeszow, Rzeszow, Poland.
Redox Rep. 2008;13(4):161-71. doi: 10.1179/135100008X259268.
Yeast flavohemoglobin (Yhb1p) plays a pivotal role in NO() detoxification and has also been implicated in oxidative/reductive stress responses. In this study, we have used a YHB1-GFP reporter expressing a full-length chromosome-tagged Yhb1-GFP fusion protein to monitor changes in flavohemoglobin levels after cell treatment with oxidants, antioxidants and nitric oxide donors. Only nitric oxide donors were found to induce a dose-dependent increase in Yhb1-GFP expression while hydrogen peroxide, menadione and diamide caused a moderate diminution of YHB1-GFP fluorescence. Additionally, the levels of endogenous and hydroperoxide-induced ROS production in the Deltayhb1 mutant were comparable to those in the isogenic wild-type strain. Although peroxides increased NO() generation while nitrite and nitric oxide donors augmented ROS levels in yeast cells, their effects were generally not more pronounced in Deltayhb1 than in wild-type cells. Taken together, these data suggest that yeast flavohemoglobin does not contribute to cross-protection against oxidative and nitrosative stress.
酵母黄素血红蛋白（Yhb1p）在一氧化氮（NO*）解毒过程中起关键作用，并且也与氧化/还原应激反应有关。在本研究中，我们使用了一个表达全长染色体标记的Yhb1-GFP融合蛋白的YHB1-GFP报告基因，来监测在用氧化剂、抗氧化剂和一氧化氮供体处理细胞后黄素血红蛋白水平的变化。仅发现一氧化氮供体可诱导Yhb1-GFP表达呈剂量依赖性增加，而过氧化氢、甲萘醌和二酰胺则导致YHB1-GFP荧光适度减弱。此外，Deltayhb1突变体中内源性和过氧化氢诱导的活性氧（ROS）产生水平与同基因野生型菌株中的相当。尽管过氧化物增加了酵母细胞中NO*的生成，而亚硝酸盐和一氧化氮供体提高了ROS水平，但它们对Deltayhb1的影响通常并不比野生型细胞更明显。综上所述，这些数据表明酵母黄素血红蛋白对氧化应激和亚硝化应激没有交叉保护作用。
