...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Redox Properties of the PutA Protein from Escherichia coli and the Influence of the Flavin Redox State on PutA-DNA Interactions
【24h】

Redox Properties of the PutA Protein from Escherichia coli and the Influence of the Flavin Redox State on PutA-DNA Interactions

机译：大肠杆菌PutA蛋白的氧化还原特性以及黄素氧化还原状态对PutA-DNA相互作用的影响

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

The PutA flavoprotein from Escherichia co/i is both a transcriptional repressor and a membrane-associated proline dehydrogenase. PutA represses transcription of the putA and putP genes by binding to the control region DNA of the put regulon (put intergenic DNA). Previous work has shown that FAD has a role in regulating the transcriptional repressor and membrane binding functions of the PutA protein. To test the influence of the FAD redox state on PutA—DNA interactions, we characterized the redox properties of the PutA flavoprotein from E. co/i. At pH 7.5, an Em(E~FAD/E~FADH2) of —0.076 V for the two-electron reduction of PutA-bound FAD was determined by potentiometric titrations. Stabilization of semiquinone species was not observed during potentiometric measurements. Dithionite reduction of PutA, however, caused formation of red anionic semiquinone. The Em value for the proline/A1-pyrroline-5-carboxylate couple was determined to be —0.123 V, demonstrating the reduction of PutA by proline is favored by a potential difference (AE0’) of more than 0.045 V. Characterization of the PutA redox properties in the presence of put intergenic DNA revealed an Em(EDNAFAD/EDNAFADH2) of —0.086 V. The 10 mV negative shift in Em corresponds to just a 2.3-fold increase in the dissociation constant of PutA with the DNA upon reduction of FAD. Thus, it appears the FAD redox state has little influence on the overall PutA—DNA interactions.
机译：大肠杆菌co / i的PutA黄素蛋白既是转录阻遏物，又是与膜相关的脯氨酸脱氢酶。 PutA通过与put regulon的控制区DNA（基因间DNA）结合而抑制putA和putP基因的转录。先前的研究表明，FAD在调节PutA蛋白的转录阻遏物和膜结合功能中具有作用。为了测试FAD氧化还原状态对PutA-DNA相互作用的影响，我们表征了来自大肠杆菌的PutA黄素蛋白的氧化还原特性。在pH 7.5下，通过电位滴定法确定了PutA结合的FAD的两电子还原的Em（E〜FAD / E〜FADH2）为-0.076V。在电位测量过程中未观察到对苯二酚种类的稳定。但是，连二亚硫酸盐还原PutA会导致形成红色阴离子半醌。脯氨酸/ A1-吡咯啉-5-羧酸酯对的Em值确定为-0.123 V，这表明脯氨酸对PutA的还原作用受到大于0.045 V的电势差（AE0'）的支持。在存在被插入的基因间DNA的情况下的氧化还原特性显示Em（EDNAFAD / EDNAFADH2）为-0.086V。Em中的10 mV负移对应于在FAD减少时PutA与DNA的解离常数仅增加2.3倍。因此，似乎FAD氧化还原状态对总体PutA-DNA相互作用几乎没有影响。

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