...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The FEBS journal >Insight into the redox regulation of the phosphoglucan phosphatase SEX4 involved in starch degradation
【24h】

Insight into the redox regulation of the phosphoglucan phosphatase SEX4 involved in starch degradation

机译：深入了解参与淀粉降解的磷酸葡聚糖磷酸酶SEX4的氧化还原调节

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

Starch is the major carbohydrate reserve in plants, and is degraded for growth at night. Starch breakdown requires reversible glucan phosphorylation at the granule surface by novel dikinascs and phosphatases. The dual-specificity phosphatase starch excess 4 (SEX4) is required for glucan des-phosphorylation; however, regulation of the enzymatic activity of SEX4 is not well understood. We show that SEX4 switches between reduced (active) and oxidized (inactive) states, suggesting that SEX4 is rcdox-rcgulatcd. Although only partial reactivation of SEX4 was achieved using artificial rc-ductants (e.g. dithiothrcitol), use of numerous chloroplastic thiorcdoxins recovered activity completely, suggesting that thiorcdoxins could reduce SEX4 in vivo. Analysisof peptides from oxidized and reduced SEX4 identified a disulfide linkage between the catalytic cysteine at position 198 (Cysl98) and the cysteine at position 130 (Cysl30) within the phosphatase domain. The position of these cysteines was structurally analogous to that for known rcdox-rcgulatcd dual-specificity phosphatases, suggesting a common mechanism of reversible oxidation amongst these phosphatases. Mutation of Cysl30 renders SEX4 more sensitive to oxidative inactivation and less responsive to reductive reactivation. Together, these results provide the first biochemical evidence for a rcdox-dcpcndcnt structural switch that regulates SEX4 activity, which represents the first plant phosphatase known to undergo reversible oxidation via disulfide bond formation like its mammalian counterparts.
机译：淀粉是植物中主要的碳水化合物储备，在夜间可降解以生长。淀粉分解需要通过新型二激酶和磷酸酶在颗粒表面进行可逆的葡聚糖磷酸化。葡聚糖去磷酸化需要双重特异性磷酸酶淀粉过量4（SEX4）;但是，对SEX4酶活性的调节尚不清楚。我们显示SEX4在还原状态（有活性）和氧化状态（无活性）之间切换，表明SEX4是rcdox-rcgulatcd。尽管使用人工rc-还原剂（例如二硫苏糖醇）仅实现了SEX4的部分活化，但使用大量的氯塑料硫代rcdoxodins可以完全恢复活性，这表明thiorcdoxins可以在体内降低SEX4的活性。对来自氧化和还原的SEX4的肽的分析确定了磷酸酶结构域中位于198位的催化半胱氨酸（Cysl98）与位于130位的半胱氨酸（Cysl30）之间的二硫键。这些半胱氨酸的位置在结构上类似于已知的rcdox-rcgulatcd双重特异性磷酸酶的位置，表明这些磷酸酶之间存在可逆氧化的常见机制。 Cysl30的突变使SEX4对氧化失活更敏感，对还原性再激活的反应更弱。总之，这些结果为调节SEX4活性的rcdox-dcpcndcnt结构开关提供了第一个生化证据，它代表第一个已知的植物磷酸酶像其哺乳动物对应物一样通过二硫键的形成可逆氧化。

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