...
  • 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 >Ultrafast infrared spectroscopy reveals a key step for successful entry into the photocycle for photoactive yellow protein
【24h】

Ultrafast infrared spectroscopy reveals a key step for successful entry into the photocycle for photoactive yellow protein

机译：超快红外光谱揭示了成功进入光敏黄色蛋白光周期的关键步骤

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

Photoactive proteins such as PYP (photoactive yellow protein) are generally accepted as model systems for studying protein signal state formation. PYP is a blue-light sensor from the bacterium Halorhodospira halophila. The formation of PYP's signaling state is initiated by trans-cis isomerization of the p-coumaric acid chromophore upon the absorption of light. The quantum yield of signaling state formation is ≈0.3. Using femtosecond visible pump/mid-IR probe spectroscopy, we investigated the structure of the very short-lived ground state intermediate (GSI) that results from an unsuccessful attempt to enter the photocycle. This intermediate and the first stable GSI on pathway into the photocycle, I_0, both have a mid-IR difference spectrum that is characteristic of a cis isomer, but only the I_0 intermediate has a chromophore with a broken hydrogen bond with the backbone N atom of Cys-69. We suggest, therefore, that breaking this hydrogen bond is decisive for a successful entry into the photocycle. The chromophore also engages in a hydrogen-bonding network by means of its pheno-late group with residues Tyr-42 and Glu-46. We have investigated the role of this hydrogen bond by exchanging the H bond-donating residue Glu-46 with the weaker H bond-donating glutamine (i.e., Gln-46). We have observed that this mutant exhibits virtually identical kinetics and product yields as WT PYP, even though during the I_0-to-I_1 transition, on the 800-ps time scale, the hydrogen bond of the chromophore with Gln-46 is broken, whereas this hydrogen bond remains intact with Glu-46.
机译：通常将诸如PYP（光敏黄色蛋白）之类的光敏蛋白作为研究蛋白质信号状态形成的模型系统。 PYP是来自嗜盐气单胞菌（Halorhodospira halophila）的蓝光传感器。在吸收光后，对香豆酸发色团的反式-顺式异构化可引发PYP信号状态的形成。信号态形成的量子产率约为0.3。使用飞秒可见光泵浦/中红外探针光谱学，我们研究了寿命很短的基态中间体（GSI）的结构，该结构是由于未能成功进入光循环而导致的。该中间体和进入光循环途径的第一个稳定的GSI I_0均具有中红外差异光谱，该光谱具有顺式异构体的特征，但只有I_0中间体的发色团的氢键与C的主链N原子断裂。半胱氨酸69。因此，我们建议打破氢键对于成功进入光循环具有决定性作用。发色团还通过其苯酚基团与Tyr-42和Glu-46残基结合在氢键网络中。我们已通过将供氢键的残基Glu-46与供氢键较弱的谷氨酰胺（即Gln-46）交换来研究了此氢键的作用。我们已经观察到该突变体表现出与WT PYP几乎相同的动力学和产物产率，即使在I_0到I_1跃迁期间，在800 ps的时间尺度上，发色团与Gln-46的氢键被破坏，而该氢键与Glu-46保持完整。

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