Identification and characterization of GmPDIL7, a soybean ER membrane-bound protein disulfide isomerase family protein
Identification and characterization of GmPDIL7, a soybean ER membrane-bound protein disulfide isomerase family protein
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DOI：
10.1111/febs.13984
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发表时间：
2017-02-01
期刊：
影响因子：
5.4
通讯作者：
Urade, Reiko
中科院分区：
文献类型：
--
作者：
Okuda, Aya;Matsusaki, Motonori;Urade, Reiko
内质网中合成的蛋白质大多具有分子内和分子间二硫键，二硫键对蛋白质的构象稳定性和功能起着重要作用。因此，真核细胞含有蛋白质二硫键形成途径，例如ER腔中的蛋白质二硫键异构酶（PDI）-ER氧化还原蛋白1（Ero 1）系统。在这项研究中，我们确定了大豆PDIL 7（GmPDIL 7），一种新的大豆ER膜结合的PDI家族蛋白，并确定其酶学性质。GmPDIL 7具有推定的N-末端信号序列、具有活性中心基序（CGHC）的硫氧还蛋白结构域和推定的C-末端跨膜区。同样，我们证明GmPDIL 7在大豆组织中普遍表达，并定位于ER膜。此外，GmPDIL 7与其他大豆PDI家族蛋白在体内和GmPDIL 7 mRNA略有上调ER应激下。在大肠杆菌中表达的重组GmPDIL 7的氧化还原电位为-187 mV，表明GmPDIL 7可以氧化未折叠的蛋白质。GmPDIL 7表现出与其他大豆PDI家族蛋白相似的二硫醇氧化酶活性水平。然而，GmPDIL 7的氧化重折叠活性低于其他大豆PDI家族蛋白。GmPDIL 7被GmERO 1充分氧化。综上所述，我们的结果表明，GmPDIL 7主要作为新生蛋白质中二硫键的供应者在ER膜上起氧化折叠的作用。数据库GmPDIL 7 cDNA的核苷酸序列数据可在日本DNA数据库（DDBJ）数据库中获得，登录号为LC 158001。5.3.4.1
Most proteins synthesized in the endoplasmic reticulum (ER) possess intramolecular and intermolecular disulfide bonds, which play an important role in the conformational stability and function of proteins. Hence, eukaryotic cells contain protein disulfide bond formation pathways such as the protein disulfide isomerase (PDI)-ER oxidoreductin 1 (Ero1) system in the ER lumen. In this study, we identified soybean PDIL7 (GmPDIL7), a novel soybean ER membrane-bound PDI family protein, and determined its enzymatic properties. GmPDIL7 has a putative N-terminal signal sequence, a thioredoxin domain with an active center motif (CGHC), and a putative C-terminal transmembrane region. Likewise, we demonstrated that GmPDIL7 is ubiquitously expressed in soybean tissues and is localized in the ER membrane. Furthermore, GmPDIL7 associated with other soybean PDI family proteins in vivo and GmPDIL7 mRNA was slightly upregulated under ER stress. The redox potential of recombinant GmPDIL7 expressed in Escherichia coli was -187 mV, indicating that GmPDIL7 could oxidize unfolded proteins. GmPDIL7 exhibited a dithiol oxidase activity level that was similar to other soybean PDI family proteins. However, the oxidative refolding activity of GmPDIL7 was lower than other soybean PDI family proteins. GmPDIL7 was well oxidized by GmERO1. Taken together, our results indicated that GmPDIL7 primarily plays a role as a supplier of disulfide bonds in nascent proteins for oxidative folding on the ER membrane.DatabaseThe nucleotide sequence data for the GmPDIL7 cDNA are available in the DNA Data Bank of Japan (DDBJ) databases under the accession numbers LC158001.EnzymeProtein disulfide isomerase: EC 5.3.4.1