Glutathiolation of proteins by glutathione disulfide S-oxide derived from S-nitrosoglutathione. Modifications of rat brain neurogranin/RC3 and neuromodulin/GAP-43.
Glutathiolation of proteins by glutathione disulfide S-oxide derived from S-nitrosoglutathione. Modifications of rat brain neurogranin/RC3 and neuromodulin/GAP-43.
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DOI：
10.1074/jbc.m008260200
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发表时间：
2001-02
期刊：
影响因子：
--
通讯作者：
J. Li;F. Huang;K. Huang
中科院分区：
文献类型：
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作者：
J. Li;F. Huang;K. Huang
S-亚硝基谷胱甘肽(GSNO)在自然降解过程中会产生多种含氮化合物和氧化的谷胱甘肽衍生物。确定了GSNO的主要分解产物为谷胱甘肽磺酸、谷胱甘肽二硫化物S氧化物(GS(O)SG)、谷胱甘肽二硫化合物S二氧化物(GSSG)和GSSG。测试了这些化合物和GSNO对大鼠脑内神经颗粒素/RC3(Ng)和神经调制素/GAP-43(Nm)的修饰效果。其中，GS(O)SG对这两种蛋白质的谷胱甘肽化作用最强；四种谷胱甘肽被结合到Ng的四个半胱氨酸残基中，两个被结合到Nm的两个半胱氨酸残基中。Ng和Nm是蛋白激酶C的两种体内底物；它们被蛋白激酶C磷酸化会削弱这两种蛋白与钙调蛋白的结合亲和力。与它们各自的未修饰形式相比，谷胱甘肽化的Ng是较差的底物，而谷胱甘肽的Nm是较好的蛋白激酶C底物。这两种蛋白的谷胱甘肽化不会改变它们与钙调蛋白的结合亲和力。用[(35)S]半胱氨酸标记的大鼠脑片用黄嘌呤/黄嘌呤氧化物酶或黄嘌呤/黄嘌呤氧化物酶与硝普钠联合处理，可引起GS(O)SG细胞水平的升高。这些处理，以及其他氧化剂的处理，都导致了蛋白质硫基化的增加；其中，免疫沉淀证实了Ng的硫基化。这些结果表明，GS(O)SG是氧化应激产生的最有效的谷胱甘肽合成剂之一。
S-Nitrosoglutathione (GSNO) undergoes spontaneous degradation that generates several nitrogen-containing compounds and oxidized glutathione derivatives. We identified glutathione sulfonic acid, glutathione disulfide S-oxide (GS(O)SG), glutathione disulfide S-dioxide, and GSSG as the major decomposition products of GSNO. Each of these compounds and GSNO were tested for their efficacies to modify rat brain neurogranin/RC3 (Ng) and neuromodulin/GAP-43 (Nm). Among them, GS(O)SG was found to be the most potent in causing glutathiolation of both proteins; four glutathiones were incorporated into the four Cys residues of Ng, and two were incorporated into the two Cys residues of Nm. Ng and Nm are two in vivo substrates of protein kinase C; their phosphorylations by protein kinase C attenuate the binding affinities of both proteins for calmodulin. When compared with their respective unmodified forms, the glutathiolated Ng was a poorer substrate and glutathiolated Nm a better substrate for protein kinase C. Glutathiolation of these two proteins caused no change in their binding affinities for calmodulin. Treatment of [(35)S]cysteine-labeled rat brain slices with xanthine/xanthine oxidase or a combination of xanthine/xanthine oxidase with sodium nitroprusside resulted in an increase in cellular level of GS(O)SG. These treatments, as well as those by other oxidants, all resulted in an increase in thiolation of proteins; among them, thiolation of Ng was positively identified by immunoprecipitation. These results show that GS(O)SG is one of the most potent glutathiolating agents generated upon oxidative stress.