...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Hydrogen bond interactions of the pheophytin electron acceptor and its radical anion in photosystem II as revealed by fourier transform infrared difference spectroscopy
【24h】

Hydrogen bond interactions of the pheophytin electron acceptor and its radical anion in photosystem II as revealed by fourier transform infrared difference spectroscopy

机译：傅里叶变换红外差光谱法揭示光脱镁电子受体及其自由基阴离子在光系统II中的氢键相互作用

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 primary electron acceptor pheophytin (Pheo_(D1)) plays a crucial role in regulation of forward and backward electron transfer in photosystem II (PSII). It is known that some cyanobacteria control the Pheo D1 potential in high-light acclimation by exchanging the D1 proteins from different copies of the psbA genes. To clarify the mechanism of the potential control of Pheo_(D1), we studied the hydrogen bond interactions of Pheo_(D1) in the neutral and anionic states using light-induced Fourier transform infrared (FTIR) difference spectroscopy. FTIR difference spectra of Pheo_(D1) upon its photoreduction were obtained using three different PSII preparations, PSII core complexes from Thermosynechococcus elongatus possessing PsbA1 as a D1 subunit (PSII-PsbA1), those with PsbA3 (PSII-PsbA3), and PSII membranes from spinach. The D1-Gln130 side chain, which is hydrogen bonded to the 13~1-keto CdOgroup of Pheo_(D1) in PSII-PsbA1, is replaced by Glu in PSII-PsbA3 and spinach PSII. The spectrum of PSII-PsbA1 exhibited 13~1-keto C=O bands at 1682 and 1605 cm~(-1) in neutral Pheo_(D1) and its anion, respectively, while the corresponding bands were observed at frequencies lower by 1-3 and 18-19 cm~(-1), respectively, in the latter two preparations. This larger frequency shift in Pheo_(D1)- than Pheo_(D1) by the change of the hydrogen bond donor was well reproduced by density functional theory (DFT) calculations for the Pheo models hydrogen bonded with acetamide and acetic acid. The DFT calculations also exhibited a higher redox potential for Pheo reduction in the model with acetic acid than that with acetamide, consistent with previous observations for the D1-Gln130Glu mutant of Synechocystis. It is thus concluded that a stronger hydrogen bond effect on the Pheo- anion than the neutral Pheo causes the shift in the redox potential, which is utilized in the photoprotection mechanism of PSII.
机译：初级电子受体脱镁叶绿素（Pheo_（D1））在光系统II（PSII）中正向和反向电子转移的调控中起着至关重要的作用。已知某些蓝细菌通过交换来自不同拷贝的psbA基因的D1蛋白来控制Pheo D1在强光驯化中的潜力。为了阐明Pheo_（D1）的电势控制机理，我们使用光诱导傅立叶变换红外（FTIR）差光谱技术研究了Pheo_（D1）在中性和阴离子状态下的氢键相互作用。使用三种不同的PSII制剂，具有PsbA1作为D1亚基（PSII-PsbA1），带有PsbA3（PSII-PsbA1）的长热嗜热球菌的PSII核心复合物，具有PsbA3（PSII-PsbA3）的PSII膜和来自PSII膜的三种II。菠菜。 PSII-PsbA3中的Glu取代了D1-Gln130侧链，该侧链与PSII-PsbA1中Pheo_（D1）的13〜1-酮CdO基氢键合。 PSII-PsbA1的光谱在中性Pheo_（D1）及其阴离子中分别在1682和1605 cm〜（-1）处显示13〜1-keto C = O谱带，而在低1的频率下观察到相应的谱带。后两种制备方法分别为3和18-19 cm〜（-1）。通过氢键供体的变化，Pheo_（D1）-比Pheo_（D1）更大的频移已通过密度泛函理论（DFT）计算，很好地重现了与乙酰胺和乙酸键合的Pheo模型。 DFT计算还显示，用乙酸比用乙酰胺在模型中还原Pheo的氧化还原电位更高，这与先前对集胞藻的D1-Gln130Glu突变体的观察结果一致。因此可以得出结论，与中性Pheo相比，对Phion-的氢键作用更强，导致氧化还原电势发生偏移，这可用于PSII的光保护机理。

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