Niedzwiedzki Dariusz M, Bar-Zvi Shira, Blankenship Robert E, Adir Noam
Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Solar Energy and Energy Storage, Washington University in St. Louis, St. Louis, MO 63130, USA; Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, MO 63130, USA.
Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Biochim Biophys Acta Bioenerg. 2019 Apr 1;1860(4):286-296. doi: 10.1016/j.bbabio.2019.01.002. Epub 2019 Jan 28.
In this study, we use ultrafast time-resolved absorption and fluorescence spectroscopies to examine A. marina phycobilisomes isolated from cells grown under light of different intensities and spectral regimes. Investigations were performed at room temperature and at 77 K. The study demonstrates that if complexes are stabilized by high phosphate (900 mM) buffer, there are no differences between them in temporal and spectral properties of fluorescence. However, when the complexes are allowed to disassemble into trimers in low phosphate (50 mM) buffer, differences are clearly observed. The fluorescence properties of intact or disassembled phycobilisomes from cells grown in low intensity white light are unresponsive to variation in phosphate concentration. This antenna complex was further studied in detail with application of femtosecond time-resolved absorption at room temperature. Combined spectroscopic and kinetic analysis of time-resolved fluorescence and absorption data of this antenna allowed us to identify spectrally different forms of phycocyanobilins and to propose a simplified model of how they could be distributed within the phycobilisome structure.
在本研究中，我们使用超快时间分辨吸收光谱和荧光光谱来检测从在不同强度和光谱条件下生长的细胞中分离出的滨海束毛藻藻胆体。研究在室温及77K下进行。该研究表明，如果复合物通过高磷酸盐（900 mM）缓冲液稳定，它们在荧光的时间和光谱特性上没有差异。然而，当复合物在低磷酸盐（50 mM）缓冲液中解离成三聚体时，差异明显可见。在低强度白光下生长的细胞中完整或解离的藻胆体的荧光特性对磷酸盐浓度的变化不敏感。在室温下应用飞秒时间分辨吸收对该天线复合物进行了进一步详细研究。对该天线的时间分辨荧光和吸收数据进行联合光谱和动力学分析，使我们能够识别出光谱上不同形式的藻蓝胆素，并提出它们在藻胆体结构中可能分布方式的简化模型。
