Cardozo Giuliana, Mastrogiovanni Mauricio, Zeida Ari, Viera Nicolás, Radi Rafael, Reyes Aníbal M, Trujillo Madia
Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay.
Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo 11800, Uruguay.
Antioxidants (Basel). 2023 Feb 7;12(2):408. doi: 10.3390/antiox12020408.
Human peroxiredoxin 3 (Prx3) is a thiol-based peroxidase responsible for the reduction of most hydrogen peroxide and peroxynitrite formed in mitochondria. Mitochondrial disfunction can lead to membrane lipoperoxidation, resulting in the formation of lipid-bound fatty acid hydroperoxides (FA-OOHs) which can be released to become free fatty acid hydroperoxides (FA-OOHs). Herein, we report that Prx3 is oxidized and hyperoxidized by FA-OOHs including those derived from arachidonic acid and eicosapentaenoic acid peroxidation at position 15 with remarkably high rate constants of oxidation (>3.5 × 10 Ms) and hyperoxidation (~2 × 10 Ms). The endoperoxide-hydroperoxide PGG, an intermediate in prostanoid synthesis, oxidized Prx3 with a similar rate constant, but was less effective in causing hyperoxidation. Biophysical methodologies suggest that Prx3 can bind hydrophobic structures. Indeed, molecular dynamic simulations allowed the identification of a hydrophobic patch near the enzyme active site that can allocate the hydroperoxide group of FA-OOHs in close proximity to the thiolate in the peroxidatic cysteine. Simulations performed using available and herein reported kinetic data indicate that Prx3 should be considered a main target for mitochondrial FA-OOHs. Finally, kinetic simulation analysis support that mitochondrial FA-OOHs formation fluxes in the range of nM/s are expected to contribute to Prx3 hyperoxidation, a modification that has been detected in vivo under physiological and pathological conditions.
人过氧化物还原酶3（Prx3）是一种基于硫醇的过氧化物酶，负责还原线粒体中形成的大多数过氧化氢和过氧亚硝酸盐。线粒体功能障碍可导致膜脂质过氧化，从而形成与脂质结合的脂肪酸氢过氧化物（FA-OOHs），后者可释放出来成为游离脂肪酸氢过氧化物（FA-OOHs）。在此，我们报告Prx3会被FA-OOHs氧化和过度氧化，包括那些源自花生四烯酸和二十碳五烯酸在15位过氧化产生的FA-OOHs，其氧化速率常数（>3.5×10 M/s）和过度氧化速率常数（~2×10 M/s）非常高。前列腺素合成中间体内过氧化物-氢过氧化物PGG以类似的速率常数氧化Prx3，但在引起过度氧化方面效果较差。生物物理方法表明Prx3可以结合疏水结构。实际上，分子动力学模拟确定了酶活性位点附近的一个疏水区域，该区域可以将FA-OOHs的氢过氧化物基团定位在过氧化物半胱氨酸中的硫醇盐附近。使用现有及本文报道的动力学数据进行的模拟表明，Prx3应被视为线粒体FA-OOHs的主要靶点。最后，动力学模拟分析支持，纳摩尔/秒范围内的线粒体FA-OOHs形成通量预计会导致Prx3过度氧化，这种修饰在生理和病理条件下的体内已被检测到。
