National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy.
Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy.
Biomolecules. 2023 Jun 15;13(6):993. doi: 10.3390/biom13060993.
The carnitine/acylcarnitine carrier (CAC) represents the route of delivering acyl moieties to the mitochondrial matrix for accomplishing the fatty acid β-oxidation. The CAC has a couple of Cys residues (C136 and C155) most reactive toward ROS and redox signaling compounds such as GSH, NO, and HS. Among physiological compounds reacting with Cys, itaconate is produced during inflammation and represents the connection between oxidative metabolism and immune responses. The possible interaction between the CAC and itaconate has been investigated.
the modulatory effects of itaconate on the transport activity of the native and recombinant CAC were tested using the proteoliposome experimental model together with site-directed mutagenesis and computational analysis.
Itaconate reacts with the CAC causing irreversible inhibition. Dose-response experiment performed with the native and recombinant protein showed IC for itaconate of 11 ± 4.6 mM and 8.4 ± 2.9 mM, respectively. The IC decreased to 3.8 ± 1.0 mM by lowering the pH from pH 7.0 to pH 6.5. Inhibition kinetics revealed a non-competitive type of inhibition. C136 is the main target of itaconate, as demonstrated by the increased IC of mutants in which this Cys was substituted by Val. The central role of C136 was confirmed by covalent docking. Administration of dimethyl itaconate to HeLa cells inhibited the CAC transport activity, suggesting that itaconate could react with the CAC also in intact cells.
肉碱/酰基辅酶 A 载体（CAC）是将酰基部分递送到线粒体基质中以完成脂肪酸β氧化的途径。CAC 有几个半胱氨酸残基（C136 和 C155）对 ROS 和氧化还原信号化合物（如 GSH、NO 和 HS）最敏感。在与 Cys 反应的生理化合物中，它庚酸在炎症期间产生，代表氧化代谢和免疫反应之间的联系。已经研究了 CAC 和它庚酸之间的可能相互作用。
使用蛋白脂质体实验模型以及定点突变和计算分析，测试了它庚酸对天然和重组 CAC 转运活性的调节作用。
它庚酸与 CAC 反应导致不可逆抑制。用天然和重组蛋白进行的剂量反应实验显示，它庚酸的 IC 分别为 11±4.6mM 和 8.4±2.9mM。将 pH 从 7.0 降低至 6.5 时，IC 降低至 3.8±1.0mM。抑制动力学显示出非竞争性抑制类型。C136 是它庚酸的主要靶标，这一点通过取代此半胱氨酸的突变体的 IC 增加得到证实。C136 的中心作用通过共价对接得到证实。向 HeLa 细胞中给予二甲基它庚酸抑制了 CAC 的转运活性，表明它庚酸也可以与 CAC 在完整细胞中反应。
