...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Probing the Redox States of Sodium Channel Cysteines at the Binding Site of mu O-Conotoxin GVIIJ
【24h】

Probing the Redox States of Sodium Channel Cysteines at the Binding Site of mu O-Conotoxin GVIIJ

机译：在mu O-芋螺毒素GVIIJ的结合位点探测钠通道半胱氨酸的氧化还原态

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

mu O -Conotoxin GVIIJ is a 35-amino acid peptide that readily blocks six of eight tested Na(V)1 subunit isoforms of voltage-gated sodium channels. mu O -GVIIJ is unusual in having an S-cysteinylated cysteine (at residue 24). A proposed reaction scheme involves the peptidechannel complex stabilized by a disulfide bond formed via thioldisulfide exchange between Cys24 of the peptide and a Cys residue at neurotoxin receptor site 8 in the pore module of the channel (specifically, Cys910 of rat Na(V)1.2). To examine this model, we synthesized seven derivatives of mu O -GVIIJ in which Cys24 was disulfide-bonded to various thiols (or SR groups) and tested them on voltage-clamped Xenopus laevis oocytes expressing Na(V)1.2. In the proposed model, the SR moiety is a leaving group that is no longer present in the final peptidechannel complex; thus, the same koff value should be obtained regardless of the SR group. We observed that all seven derivatives, whose kon values varied over a 30-fold range, had the same koff value. Concordant results were observed with Na(V)1.6, for which the koff was 17-fold larger. Additionally, we tested two mu O -GVIIJ derivatives (where SR was glutathione or a free thiol) on two Na(V)1.2 Cys replacement mutants (Na(V)1.2[C912A] and Na(V)1.2[C918A]) without and with reduction of channel disulfides by dithiothreitol. The results indicate that Cys910 in wild-type Na(V)1.2 has a free thiol and conversely suggest that in Na(V)1.2[C912A] and Na(V)1.2[C918A], Cys910 is disulfide-bonded to Cys918 and Cys912, respectively. Redox states of extracellular cysteines of sodium channels have hitherto received scant attention, and further experiments with GVIIJ may help fill this void.
机译：mu O-Conotoxin GVIIJ是一种35个氨基酸的肽段，可轻易阻断电压门控钠通道的八个经过测试的Na（V）1亚基异构体中的六个。 mu O -GVIIJ具有S-半胱氨酸化的半胱氨酸是不寻常的（在残基24处）。拟议的反应方案涉及通过肽的Cys24与通道孔模块中神经毒素受体位点8上的Cys残基之间的巯基二硫键交换形成的二硫键稳定的肽通道复合物（特别是大鼠Na（V）1.2的Cys910） 。为了检查该模型，我们合成了mu O -GVIIJ的七个衍生物，其中Cys24二硫键与各种硫醇（或SR基团）结合，并在表达Na（V）1.2的电压钳制非洲爪蟾卵母细胞上对其进行了测试。在提出的模型中，SR部分是一个离去基团，该残基不再存在于最终的肽通道复合物中。因此，无论SR组如何，都应获得相同的koff值。我们观察到kon值在30倍范围内变化的所有七个导数具有相同的koff值。用Na（V）1.6观察到一致的结果，其koff值大17倍。此外，我们在没有两个Na（V）1.2 Cys替代突变体（Na（V）1.2 [C912A]和Na（V）1.2 [C918A]）上测试了两个mu O -GVIIJ衍生物（其中SR是谷胱甘肽或游离硫醇）并通过二硫苏糖醇还原通道二硫化物。结果表明，野生型Na（V）1.2中的Cys910具有游离硫醇，反过来表明在Na（V）1.2 [C912A]和Na（V）1.2 [C918A]中，Cys910与Sys918和Cys912二硫键结合， 分别。迄今为止，钠通道的细胞外半胱氨酸的氧化还原状态一直很少受到关注，GVIIJ的进一步实验可能有助于填补这一空白。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号