Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
Chem Commun (Camb). 2018 Jun 8;54(47):5992-5995. doi: 10.1039/c8cc01339j.
The bacterial nitric oxide (NO)-sensing transcriptional regulator NsrR binds a [4Fe-4S] cluster that enables DNA-binding and thus repression of the cell's NO stress response. Upon exposure to NO, the cluster undergoes a complex nitrosylation reaction resulting in a mixture of iron-nitrosyl species, which spectroscopic studies have indicated are similar to well characterized low molecular weight dinitrosyl iron complex (DNIC), Roussin's Red Ester (RRE) and Roussin's Black Salt (RBS). Here we report mass spectrometric studies that enable the unambiguous identification of NsrR-bound RRE-type species, including a persulfide bound form that results from the oxidation of cluster sulfide. In the presence of the low molecular weight thiols glutathione and mycothiol, glutathionylated and mycothiolated forms of NsrR were readily formed.
细菌一氧化氮（NO）感应转录调控因子 NsrR 结合一个 [4Fe-4S] 簇，该簇能够进行 DNA 结合，从而抑制细胞的 NO 应激反应。在暴露于 NO 后，该簇经历复杂的亚硝基化反应，产生一系列铁-亚硝酰物种，光谱研究表明这些物种类似于特征明确的低分子量二硝酰铁配合物（DNIC）、Roussin 的红酯（RRE）和 Roussin 的黑盐（RBS）。本研究通过质谱研究明确鉴定了与 NsrR 结合的 RRE 型物种，包括由簇硫代物氧化产生的过硫化物结合形式。在低分子量巯基化合物谷胱甘肽和 mycothiol 存在下，很容易形成 NsrR 的谷胱甘肽化和 mycothiol 化形式。
