Studies on the reducing systems for plant and animal thioredoxin-independent methionine sulfoxide reductases B
Studies on the reducing systems for plant and animal thioredoxin-independent methionine sulfoxide reductases B
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DOI：
10.1016/j.bbrc.2007.07.072
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发表时间：
2007-09-28
影响因子：
3.1
通讯作者：
Zhang, Xing-Hal
中科院分区：
文献类型：
--
作者：
Ding, Di;Sagher, Daphna;Zhang, Xing-Hal
两种不同的立体定向蛋氨酸亚砜还原酶MsrA和MsrB将氧化的蛋氨酸（Met），蛋氨酸亚砜[Met(O)]还原为Met。在本报告中，我们研究了烟草（Nicotiana tabacum）中两种绿塑性MsrB酶（NtMsrB1和NtMsrB2）活性所需的还原系统。我们发现NtMrsB1，而不是NtMsrB2，可以使用二硫苏糖醇作为有效的氢供体。相比之下，大肠杆菌硫氧还蛋白（Trx）可以作为NtMsrB2的还原剂，但不能作为NtMsrB1的还原剂。与先前报道的不依赖trx的hMsrB2和hMsrB3类似，NtMsrB1也可以使用牛肝硫蛋白和硒代半胱胺作为还原剂。此外，独特的植物trx样蛋白CDSP32被证明可以减少NtMsrB1， hMsrB2和hMsrB3。所有这些被测试的trx非依赖性MsrB酶都缺乏一个额外的半胱氨酸（分解半胱氨酸），该半胱氨酸能够在催化反应中在酶上形成二硫键。我们的研究结果表明，缺乏分解半胱氨酸的植物和动物MsrB酶可能具有相似的反应机制。(c) 2007爱思唯尔公司版权所有。
Two distinct stereospecific methionine sulfoxide reductases (Msr), MsrA and MsrB reduce the oxidized methionine (Met), methionine sulfoxide [Met(O)], back to Met. In this report, we examined the reducing systems required for the activities of two chloroplastic MsrB enzymes (NtMsrB1 and NtMsrB2) from tobacco (Nicotiana tabacum). We found that NtMrsB1, but not NtMsrB2, could use dithiothreitol as an efficient hydrogen donor. In contrast Escherichia coli thioredoxin (Trx) could serve as a reducing agent for NtMsrB2, but not for NtMsrB1. Similar to previously reported human Trx-independent hMsrB2 and hMsrB3, NtMsrB1 could also use bovine liver thionein and selenocysteamine as reducing agents. Furthermore, the unique plant Trx-like protein CDSP32 was shown to reduce NtMsrB1, hMsrB2 and hMsrB3. All these tested Trx-independent MsrB enzymes lack an additional cysteine (resolving cysteine) that is capable of forming a disulfide bond on the enzyme during the catalytic reaction. Our results indicate that plant and animal MsrB enzymes lacking a resolving cysteine likely share a similar reaction mechanism. (c) 2007 Elsevier Inc. All rights reserved.