光系统Ⅱ反应中心D_1-D_2-Cyt b_(559)复合物低温(77K)荧光发射差异的研究

对菠菜光系统Ⅱ反应中心D_1-D_2-Cytb_(559)复合物进行了系统的低温(77K)荧光发射性质研究。结果表明,D_1-D_2-Cytb_(559)复合物具有681nm和684nm两种波长的低温荧光发射,但两者通常并不是同时存在,而是取决于Ca-680与Ca-670Chla分子的相对含量的。Ca-670Chla含量的增加,会使其低温荧光发射出现在681nm;而Ca-680Chla含量的增加,则会使其低温荧光发射出现在684nm。Ca-670与Ca-680Chla分子的相对含量与不同状态的菠菜叶材料有关。PSⅡ反应中心内周天线CP-47,CP-43多肽的存在是D_1-D_2-Cytb_(591)复合物低温荧光发射红移的原因,而D_1-D_2-Cytb_(559)复合物的不稳定变化则与其蓝移的低温荧光发射有关。

THE STUDY ON 77K FLUORESCENCE EMISSION PROPERTIES OF PS I REACTION CENTER COMPLEX D_1-D_2-CYT B_559

This paper presents a detail study on 77K fluorescence emission proper-tics of D1-D2-Cyt b559complex isolated from spinach leaves. It Was showed that D1-D2-Cyt b559 complex had 77K fluorescence emission at either 681 nm or 684 nm, depending on the relative amounts of Ca-670 and Ca-680 Chl-a molecules. The increase of Ca-670 Chl-a molecules caused the blue-shift of 77K fluorescence emission of the complex to 681 nm, whereas the increase of Ca-680 Chl-a molecules might result in the 77K fluorescence emission at 684 nm. The relative amount of Ca-670 and Ca-680 Chl-a molecules was related to the pre-experi-mental conditions of spinach leaves. It nas also showed that the red-shift 77K fluorescence emission might be related to the existence of PS I 's intermediate antenna Chl-proteins CP-47 and CP-43, while the destability of the isolated D1-D2-Cyt b559 complex might be the main cause of the complex' blue-shift 77K fluorescence emission. These results, as concluded, might be helpful to explain the current discrepancy of the 77K fluorescence emission properties of D1-D2-Cyt b559complex.