光系统Ⅱ核心天线CP47热稳定性的荧光动力学

采用激励光源为4MHz、514.5nm的分幅扫描单光子计数荧光装置对从菠菜中分离提纯的核心天线CP47的热稳定性进行研究,得到经20℃、42℃和48℃处理后的动力学三维荧光谱.它们在最大峰值处的时间常量及其chla分子发射荧光的效率分别为:20℃:2.849ns(43.60%),4.024ns(35.37%);42℃:2.107ns(51.11%),3.657ns(37.59%);48℃:3.801ns(36.69%),4.0149ns(34.68%).因此,在CP47中存在有2组处于不同聚合状态的chla分子,3个处理温度中较短的时间组分属于2组中处于同一种聚合状态色素分子之间chla→chla→chla基态的能量传递时间,较长的时间组分属于2组处于不同聚合状态色素分子之间chla→chla→chla基态的能量传递时间.CP47中,20℃～42℃之间的温度对蛋白质空间结构的影响较小,与蛋白质结合的2种结合状态的chla分子之间的空间位置改变也较少.而42℃～48℃之间的温度引起较大的蛋白质空间结构和与蛋白质结合的2种结合状态的chla分子之间的空间位置改变.

Fluorescence Dynamics on Thermal Stability of Inner Antenna CP47 in PS Ⅱ

Thermal stability of inner antenna CP47 were studied by using fluorescence dynamics. CP47 were treated at 20℃, 42℃,48℃ respectively and their three-dimensional dynamic fluorescence spectrum were gotten.The fluorescence lifetime at maximum peak and chla emissiom efficiencies were: 20℃:2.849 ns(43.60%), 4.024 ns(35.37%);42℃;2.107 ns(51.11%),3.657 ns(37.59%);48℃:3.801 ns(36.69%),4.0149 ns (34.68%).Therefore, CP47 had two series of chla molecules under different conditions. The shotter lifetimes were the time needed by energy transportation from chla to chla ground state within two series of chla molecules, the longer ones were the time needed by energy transportation from chla to chla ground state between two series of chla molecules. In CP47, the protein conformation and chla spatial orientation were affected a little between 20℃ and 42℃. While, between 42℃ and 48℃, they had distinct changes.