Park Joung Hun, Lee Eun Seon
Division of Ecological Threat Management, National Institute of Ecology, 1210 Geumgang-ro, Maseo-myeon, Seocheon, Republic of Korea.
Division of Ecological Threat Management, National Institute of Ecology, 1210 Geumgang-ro, Maseo-myeon, Seocheon, Republic of Korea.
Biochem Biophys Res Commun. 2025 Sep 1;777:152329. doi: 10.1016/j.bbrc.2025.152329. Epub 2025 Jul 9.
Thioredoxin (Trx) functions as a disulfide reductase, regulating the redox state of proteins. Arabidopsis Trx-h types are classified into three subgroups based on their N-terminal extension region and lipid modifications. Not all Trx-h type functions have been fully unraveled. In this study, the molecular functions of Trx-h7 were studied. Trx-h7 contains the redox-active site motif WCGPC and consists of 129 amino acids. To investigate the molecular functions of the Trx-h7, we measured its insulin reductase activity, holdase chaperone activity, and DNA-binding activity. The insulin reductase activity of Trx-h7 was significantly lower than that of Trx-h2 but increased with increasing Trx-h7 protein concentration. Like Trx-h2, Trx-h7 showed no holdase chaperone activity. Trx-h7 had low binding affinity for single-stranded DNA, but high binding affinity for double-stranded DNA. These results indicate that Trx-h7, as a disulfide reductase, regulates the redox status of its target protein and binds to dsDNA.
硫氧还蛋白（Trx）作为一种二硫键还原酶，调节蛋白质的氧化还原状态。拟南芥Trx-h类型根据其N端延伸区域和脂质修饰分为三个亚组。并非所有Trx-h类型的功能都已完全阐明。在本研究中，对Trx-h7的分子功能进行了研究。Trx-h7包含氧化还原活性位点基序WCGPC，由129个氨基酸组成。为了研究Trx-h7的分子功能，我们测量了其胰岛素还原酶活性、保持伴侣活性和DNA结合活性。Trx-h7的胰岛素还原酶活性显著低于Trx-h2，但随着Trx-h7蛋白浓度的增加而增加。与Trx-h2一样，Trx-h7没有显示出保持伴侣活性。Trx-h7对单链DNA的结合亲和力较低，但对双链DNA的结合亲和力较高。这些结果表明，Trx-h7作为一种二硫键还原酶，调节其靶蛋白的氧化还原状态并与双链DNA结合。
