...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Designing a functional type 2 copper center that has nitrite reductase activity within α-helical coiled coils
【24h】

Designing a functional type 2 copper center that has nitrite reductase activity within α-helical coiled coils

机译：设计在α螺旋线圈中具有亚硝酸还原酶活性的功能性2型铜中心

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

One of the ultimate objectives of de novo protein design is to realize systems capable of catalyzing redox reactions on substrates. This goal is challenging as redox-active proteins require design considerations for both the reduced and oxidized states of the protein. In this paper, we describe the spectroscopic characterization and catalytic activity of a de novo designed metallopeptide Cu(Ⅰ/Ⅱ)(TRIL23H)_3~(+/2+). where Cu(Ⅰ/Ⅱ) is embeded in α-helical coiled coils, as a model for the Cu_(T2) center of copper nitrite reductase. In Cu(Ⅰ/Ⅱ)(TRIL23H)_3~(+/2+), Cu(Ⅰ) is coordinated to three histidines, as indicated by X-ray absorption data, and Cu(Ⅱ) to three histidines and one or two water molecules. Both ions are bound in the interior of the three-stranded coiled coils with affinities that range from nano- to micromolar [Cu(Ⅱ)], and picomolar [Cu(Ⅰ)]. The Cu (His)_3 active site is characterized in both oxidation states, revealing similarities to the Cu_(T2) site in the natural enzyme. The species Cu(Ⅱ) (TRIL23H)_3~(2+) in aqueous solution can be reduced to Cu(Ⅰ)(TRIL23H)_3~+ using ascorbate, and reoxidized by nitrite with production of nitric oxide. At pH 5.8, with an excess of both the reductant (ascorbate) and the substrate (nitrite), the copper peptide Cu(Ⅱ)(TRIL23H)_3~(2+) acts as a catalyst for the reduction of nitrite with at least five turnovers and no loss of catalytic efficiency after 3.7 h. The catalytic activity, which is first order in the concentration of the peptide, also shows a pH dependence that is described and discussed.
机译：从头设计蛋白质的最终目的之一是实现能够催化底物上氧化还原反应的系统。该目标具有挑战性，因为氧化还原活性蛋白需要针对该蛋白的还原态和氧化态进行设计考虑。本文描述了一种从头设计的金属肽Cu（Ⅰ/Ⅱ）（TRIL23H）_3〜（+ / 2+）的光谱表征和催化活性。作为亚硝酸铜还原酶Cu_（T2）中心的模型，其中Cu（Ⅰ/Ⅱ）嵌入在α螺旋线圈中。 X射线吸收数据表明，在Cu（Ⅰ/Ⅱ）（TRIL23H）_3〜（+ / 2+）中，Cu（Ⅰ）与3个组氨酸配位，Cu（Ⅱ）与3个组氨酸和1或2个配位。水分子。两种离子都结合在三链盘绕线圈的内部，亲和力范围从纳摩尔到微摩尔[Cu（Ⅱ）]和皮摩尔[Cu（Ⅰ）]。 Cu（His）_3活性位点在两种氧化状态下均具有特征，显示与天然酶中的Cu_（T2）位点相似。水溶液中的Cu（Ⅱ）（TRIL23H）_3〜（2+）可通过抗坏血酸盐还原为Cu（Ⅰ）（TRIL23H）_3〜+，并通过亚硝酸盐再氧化生成一氧化氮。在pH 5.8的条件下，还原剂（抗坏血酸盐）和底物（亚硝酸盐）都过量，铜肽Cu（Ⅱ）（TRIL23H）_3〜（2+）用作至少还原五种亚硝酸盐的催化剂3.7小时后，其周转率和催化效率均没有损失。催化活性是肽浓度的第一级，也显示了所描述和讨论的pH依赖性。

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