Argyroudi A J, Akoyunoglou G
Arch Biochem Biophys. 1983 Dec;227(2):469-77. doi: 10.1016/0003-9861(83)90477-0.
To investigate further the possibility that changes in the organization of the thylakoid pigment-protein complexes are monitored by the chlorophyll a fluorescence yield changes, or by changes in the F685/F730 ratio in the 77 degrees K fluorescence, as earlier proposed (A. Castorinis, G. Akoyunoglou, and J.H. Argyroudi-Akoyunoglou (1982) Photobiochem. Photobiophys. 4, 283-291; J.H. Argyroudi-Akoyunoglou, A. Castorinis, and G. Akoyunoglou (1982) Photobiochem. Photobiophys. 4, 201-210), the effect of pH, Cd2+ or Zn2+ addition, and trypsinization on all parameters was studied. We found that (a) the pH of the medium affects the ratio of oligomeric to monomeric structures of the complexes (monomers predominate at low pH), as well as the ratio F685/F730 of thylakoids or of the isolated CPIa complex (the F685/F730 ratio is high at low pH, and low at high). (b) Zn2+ or Cd2+ addition to thylakoids, suspended in Tricine (N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine), has no effect on the chlorophyll a fluorescence yield nor on the F685/F730 ratio at 77 degrees K; similarly, no effect can be noticed on the F685/F730 ratio at 77 degrees K of the isolated CPIa complex. These cations, contrary to Mg2+, do not affect the oligomer to monomer dissociation, but they instead reverse the cation effect and enhance the oligomeric structures. (c) Trypsinized thylakoids in Tricine do not show the Mg2+ effect on the chlorophyll a fluorescence yield, have a reduced F730/F685 ratio at 77 degrees K, and are deficient in the CPIa complex, which is mainly responsible for the F685/F730 ratio changes in the presence of cations. The results support the proposal that cation- or pH-induced changes in the chlorophyll a fluorescence yield at room temperature, or in the F685/F730 ratio at 77 degrees K, are irrelevant to the excitation energy distribution between the two photosystems. They instead seem to reflect changes in the organization of the supramolecular structure of the pigment-protein complexes in the photosystem I and photosystem II units.
为了进一步研究类囊体色素 - 蛋白质复合物组织变化是否如先前所提出的那样（A. Castorinis、G. Akoyunoglou和J.H. Argyroudi - Akoyunoglou（1982年）《光生物化学与光生物物理学》4，283 - 291；J.H. Argyroudi - Akoyunoglou、A. Castorinis和G. Akoyunoglou（1982年）《光生物化学与光生物物理学》4，201 - 210）通过叶绿素a荧光产率变化或77K荧光中F685/F730比值变化来监测，我们研究了pH值、添加Cd²⁺或Zn²⁺以及胰蛋白酶处理对所有参数的影响。我们发现：（a）介质的pH值会影响复合物的寡聚体与单体结构的比例（低pH时单体占主导），以及类囊体或分离的CPIa复合物的F685/F730比值（低pH时F685/F730比值高，高pH时低）。（b）向悬浮在三（羟甲基）甲基甘氨酸中的类囊体添加Zn²⁺或Cd²⁺，对叶绿素a荧光产率以及77K时的F685/F730比值均无影响；同样，对分离的CPIa复合物在77K时的F685/F730比值也无影响。与Mg²⁺相反，这些阳离子不会影响寡聚体到单体的解离，但它们会逆转阳离子效应并增强寡聚体结构。（c）在三（羟甲基）甲基甘氨酸中经胰蛋白酶处理的类囊体未表现出Mg²⁺对叶绿素a荧光产率的影响，在77K时F730/F685比值降低，并且缺乏CPIa复合物，而在存在阳离子时，CPIa复合物主要负责F685/F730比值的变化。这些结果支持了这样的观点，即室温下阳离子或pH诱导的叶绿素a荧光产率变化，或77K时F685/F730比值变化，与两个光系统之间的激发能分布无关。相反，它们似乎反映了光系统I和光系统II单元中色素 - 蛋白质复合物超分子结构组织的变化。
