Laboratório de Biologia Molecular de Patógenos, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
Front Cell Infect Microbiol. 2021 Nov 11;11:773410. doi: 10.3389/fcimb.2021.773410. eCollection 2021.
faces a variety of environmental scenarios during its life cycle, which include changes in the redox environment that requires a fine regulation of a complex antioxidant arsenal of enzymes. Reversible posttranslational modifications, as lysine acetylation, are a fast and economical way for cells to react to environmental conditions. Recently, we found that the main antioxidant enzymes, including the mitochondrial superoxide dismutase A (TcSODA) are acetylated , suggesting that protein acetylation could participate in the oxidative stress response in . Therefore, we investigated whether mitochondrial lysine deacetylase TcSir2rp3 was involved in the activity control of TcSODA. We observed an increased resistance to hydrogen peroxide and menadione in parasites overexpressing TcSir2rp3. Increased resistance was also found for benznidazole and nifurtimox, known to induce reactive oxidative and nitrosactive species in the parasite, associated to that a reduction in the ROS levels was observed. To better understand the way TcSir2rp3 could contributes to oxidative stress response, we analyzed the expression of TcSODA in the TcSir2rp3 overexpressing parasites and did not detect any increase in protein levels of this enzyme. However, we found that these parasites presented higher levels of superoxide dismutase activity, and also that TcSir2rp3 and TcSODA interacts . Knowing that TcSODA is acetylated at lysine residues K44 and K97, and that K97 is located at a similar region in the protein structure as K68 in human manganese superoxide dismutase (MnSOD), responsible for regulating MnSOD activity, we generated mutated versions of TcSODA at K44 and K97 and found that replacing K97 by glutamine, which mimics an acetylated lysine, negatively affects the enzyme activity . By using molecular dynamics approaches, we revealed that acetylation of K97 induces specific conformational changes in TcSODA with respect to hydrogen-bonding pattern to neighbor residues, suggesting a key participation of this residue to modulate the affinity to . Taken together, our results showed for the first time the involvement of lysine acetylation in the maintenance of homeostatic redox state in trypanosomatids, contributing to the understanding of mechanisms used by to progress during the infection.
在其生命周期中， faces a variety of environmental scenarios 面临着多种环境情景，其中包括氧化还原环境的变化，这需要精细调节复杂的抗氧化酶 Arsenal 。可逆的翻译后修饰，如赖氨酸乙酰化，是细胞对环境条件做出反应的一种快速而经济的方式。最近，我们发现主要的抗氧化酶，包括线粒体超氧化物歧化酶 A（TcSODA）被乙酰化，这表明蛋白质乙酰化可能参与到 中的氧化应激反应。因此，我们研究了线粒体赖氨酸去乙酰化酶 TcSir2rp3 是否参与 TcSODA 的活性控制。我们观察到过表达 TcSir2rp3 的寄生虫对过氧化氢和 Menadione 的抗性增加。还发现对苯并咪唑和硝呋替莫的抗性增加，已知这两种药物在寄生虫中诱导活性氧化和亚硝态氮物种，同时观察到 ROS 水平降低。为了更好地理解 TcSir2rp3 如何有助于氧化应激反应，我们分析了 TcSir2rp3 过表达寄生虫中 TcSODA 的表达，并未检测到该酶蛋白水平的任何增加。然而，我们发现这些寄生虫表现出更高水平的超氧化物歧化酶活性，并且 TcSir2rp3 和 TcSODA 相互作用。已知 TcSODA 在赖氨酸残基 K44 和 K97 处被乙酰化，并且 K97 位于蛋白质结构中与人类锰超氧化物歧化酶（MnSOD）中的 K68 相似的区域，负责调节 MnSOD 活性，我们生成了 TcSODA 在 K44 和 K97 处的突变版本，并发现将 K97 替换为谷氨酰胺，模拟乙酰化的赖氨酸，会对酶活性产生负面影响。通过使用分子动力学方法，我们揭示了 K97 的乙酰化诱导 TcSODA 相对于氢键模式与邻近残基的特定构象变化，表明该残基对调节与 亲和力具有关键作用。总之，我们的研究结果首次表明赖氨酸乙酰化参与了锥虫体内稳态氧化还原状态的维持，有助于理解 在感染过程中进展所使用的机制。
