Heat denaturation is an important technique in the study of the structure and function of photosynthetic proteins. Heat denaturation of photosystem II (PSII) membrane was studied using circular dichroism (CD) spect...Heat denaturation is an important technique in the study of the structure and function of photosynthetic proteins. Heat denaturation of photosystem II (PSII) membrane was studied using circular dichroism (CD) spectroscopy, differential scanning calorimetry (DSC) and oxygen electrode. Complete loss of oxygen evolving activity of the PSII membrane was observed at temperatures below 45℃ . The decrease of excitonic interaction between chlorophyll molecules occurred more rapidly than the change of the protein secondary structure of the PSII membrane at temperatures above 45℃ . The results indicate that the protein secondary structure of the membrane proteins in PSII membranes is more stable than the excitonic interaction between chlorophyll molecules during heat denaturation. 展开更多
The ettect of anionic phosphatidylglycerol (HG) on oxygen evolution in a photosystem Ⅱ (PS Ⅱ) particle depleted of Ca2+ (designated dCaPS Ⅱ) has been investigated. The major finding is the observation of a new role...The ettect of anionic phosphatidylglycerol (HG) on oxygen evolution in a photosystem Ⅱ (PS Ⅱ) particle depleted of Ca2+ (designated dCaPS Ⅱ) has been investigated. The major finding is the observation of a new role of PG in the PS Ⅱ function. That is, PG restores nearly the lost oxygen evolution in dCaPS Ⅱ particle owing to Ca2+ depletion to the levels in intact PS Ⅱ . Furthermore, there is a stimulation of oxygen-evolving activity in the dCaPSⅡ complexed with PG in the presence of exogenous CaCI2, which PG enhances increasingly oxygen evolution with increasing CaCI2 concentration. It is suggested that PG-induced oxygen evolution recovery of dCa PS Ⅱresumption of normal structure in protein by PG effect, whereas the enhancement of oxygen evolution in complex subject to CaCI2 is ascribed to the optimization of such a structure due to coordination complex formation of Ca2+ ions with PG.展开更多
基金Supported by the State Key Basic Research and Development Plan (No.G19980 10 10 0 ) the National Natural Science Foundation of China(No.3 9890 3 90 )
文摘Heat denaturation is an important technique in the study of the structure and function of photosynthetic proteins. Heat denaturation of photosystem II (PSII) membrane was studied using circular dichroism (CD) spectroscopy, differential scanning calorimetry (DSC) and oxygen electrode. Complete loss of oxygen evolving activity of the PSII membrane was observed at temperatures below 45℃ . The decrease of excitonic interaction between chlorophyll molecules occurred more rapidly than the change of the protein secondary structure of the PSII membrane at temperatures above 45℃ . The results indicate that the protein secondary structure of the membrane proteins in PSII membranes is more stable than the excitonic interaction between chlorophyll molecules during heat denaturation.
文摘The ettect of anionic phosphatidylglycerol (HG) on oxygen evolution in a photosystem Ⅱ (PS Ⅱ) particle depleted of Ca2+ (designated dCaPS Ⅱ) has been investigated. The major finding is the observation of a new role of PG in the PS Ⅱ function. That is, PG restores nearly the lost oxygen evolution in dCaPS Ⅱ particle owing to Ca2+ depletion to the levels in intact PS Ⅱ . Furthermore, there is a stimulation of oxygen-evolving activity in the dCaPSⅡ complexed with PG in the presence of exogenous CaCI2, which PG enhances increasingly oxygen evolution with increasing CaCI2 concentration. It is suggested that PG-induced oxygen evolution recovery of dCa PS Ⅱresumption of normal structure in protein by PG effect, whereas the enhancement of oxygen evolution in complex subject to CaCI2 is ascribed to the optimization of such a structure due to coordination complex formation of Ca2+ ions with PG.
