Photodamage of some pigments in the isolated photosystem Ⅱ (PS Ⅱ) reaction center D1/D2/Cyt b559 complex from spinach has been investigated by means of high performance liquid chromatography. The light induced damag...Photodamage of some pigments in the isolated photosystem Ⅱ (PS Ⅱ) reaction center D1/D2/Cyt b559 complex from spinach has been investigated by means of high performance liquid chromatography. The light induced damage of pheophytin a (pheo a) in the complex was observed for the first time. The content of pheo a decreased about 47% by illumination, suggesting only one of the two pheo a molecules in the PSⅡ reaction center complex was damaged. No damage of β carotene was found.展开更多
Photodamage of pheophytin a (pheo a) in the isolated photosystem Ⅱ (PSⅡ) reaction center D1/D2/Cyt b559 complex from spinach has been investigated by high performance liquid chromatographic method in detail. The res...Photodamage of pheophytin a (pheo a) in the isolated photosystem Ⅱ (PSⅡ) reaction center D1/D2/Cyt b559 complex from spinach has been investigated by high performance liquid chromatographic method in detail. The results showed that: (1) There is one pheo a molecule which is not associated with the primary photochemistry in the PSⅡ reaction center complex. It may be considered that there are two different electron transfer branches in the PSⅡ reaction center just as in the purple bacterium photosynthetic reaction center. (2) The damaged pheo a may be attributed to the one bonding to the D2 protein comparing the D2 subunit in the PSⅡ reaction center with M subunit in the purple bacterium photosynthetic reaction center. (3) A possible arrangement model of redox cofactors in the PSⅡ reaction center was proposed based on our experiment.展开更多
Fluorescence spectra of native purple bacterial reaction center (RC) and bacterial pheophytin (Bphe) replaced RCs were obtained from 600 nm to 900 nm with a selective excitation at 597 nm. With the help of measuring ...Fluorescence spectra of native purple bacterial reaction center (RC) and bacterial pheophytin (Bphe) replaced RCs were obtained from 600 nm to 900 nm with a selective excitation at 597 nm. With the help of measuring the fluorescence from bacterial chlorophyll, bacterial pheophytin and plant pheophytin, the corresponding components in the RCs are classified for fluorescence emission. Results showed that pheophytin substitution influences the composition of fluorescence spectra. Therefore, four, three and two components were obtained from fluorescence spectra of native RC, Bphe B_replaced RC and Bphe A,B _replaced RC, respectively. Fluorescence components are well correlated to the binding of plant pheophytin. The decay of excited state of primary electron donor P in different RCs was also studied by measuring the fluorescence decay at 686.4, 674.1 and 681.1 nm, respectively. The decaying kinetics changed in different RCs, indicating that pheophytin replacement influenced the energy transduction and primary photochemical reaction in purple bacterial reaction centers.展开更多
文摘Photodamage of some pigments in the isolated photosystem Ⅱ (PS Ⅱ) reaction center D1/D2/Cyt b559 complex from spinach has been investigated by means of high performance liquid chromatography. The light induced damage of pheophytin a (pheo a) in the complex was observed for the first time. The content of pheo a decreased about 47% by illumination, suggesting only one of the two pheo a molecules in the PSⅡ reaction center complex was damaged. No damage of β carotene was found.
文摘Photodamage of pheophytin a (pheo a) in the isolated photosystem Ⅱ (PSⅡ) reaction center D1/D2/Cyt b559 complex from spinach has been investigated by high performance liquid chromatographic method in detail. The results showed that: (1) There is one pheo a molecule which is not associated with the primary photochemistry in the PSⅡ reaction center complex. It may be considered that there are two different electron transfer branches in the PSⅡ reaction center just as in the purple bacterium photosynthetic reaction center. (2) The damaged pheo a may be attributed to the one bonding to the D2 protein comparing the D2 subunit in the PSⅡ reaction center with M subunit in the purple bacterium photosynthetic reaction center. (3) A possible arrangement model of redox cofactors in the PSⅡ reaction center was proposed based on our experiment.
基金The State Key Basic Research and Development Plan(G1998010100)the National Natural Science Foundation of China(39870161).
文摘Fluorescence spectra of native purple bacterial reaction center (RC) and bacterial pheophytin (Bphe) replaced RCs were obtained from 600 nm to 900 nm with a selective excitation at 597 nm. With the help of measuring the fluorescence from bacterial chlorophyll, bacterial pheophytin and plant pheophytin, the corresponding components in the RCs are classified for fluorescence emission. Results showed that pheophytin substitution influences the composition of fluorescence spectra. Therefore, four, three and two components were obtained from fluorescence spectra of native RC, Bphe B_replaced RC and Bphe A,B _replaced RC, respectively. Fluorescence components are well correlated to the binding of plant pheophytin. The decay of excited state of primary electron donor P in different RCs was also studied by measuring the fluorescence decay at 686.4, 674.1 and 681.1 nm, respectively. The decaying kinetics changed in different RCs, indicating that pheophytin replacement influenced the energy transduction and primary photochemical reaction in purple bacterial reaction centers.
