Effects of Photosystem Ⅱ (PS Ⅱ) extrinsic polypeptides of oxygen-evolving complex and manganese clusters on PS Ⅱ carbonic anhydrase (CA) were studied with spinach PS Ⅱ membranes. The result supported that membrane...Effects of Photosystem Ⅱ (PS Ⅱ) extrinsic polypeptides of oxygen-evolving complex and manganese clusters on PS Ⅱ carbonic anhydrase (CA) were studied with spinach PS Ⅱ membranes. The result supported that membrane-bound CA is located in the donor side of PS Ⅱ. The extrinsic polypeptides played an important role of maintaining CA activity. After removing manganese clusters, oxygen evolution activity was inhibited, but PSⅡ-CA activity was unchanged. It was concluded that CA activity is independent of the presence of manganese clusters, and was not directly correlated with oxygen evolution activity.展开更多
Water oxidation is one of the most important reactions in natural and artificial energy conversion schemes.In nature,solar energy is converted to chemical energy via water oxidation at the oxygen-evolving center of ph...Water oxidation is one of the most important reactions in natural and artificial energy conversion schemes.In nature,solar energy is converted to chemical energy via water oxidation at the oxygen-evolving center of photosystem II to generate dioxygen,protons,and electrons.In artificial energy schemes,water oxidation is one of the half reactions of water splitting,which is an appealing strategy for energy conversion via photocatalytic,electrocatalytic,or photoelectrocatalytic processes.Because it is thermodynamically unfavorable and kinetically slow,water oxidation is the bottleneck for achieving large-scale water splitting.Thus,developing highly efficient water oxidation catalysts has attracted the interests of researchers in the past decades.The formation of O-O bonds is typically the rate-determining step of the water oxidation catalytic cycle.Therefore,better understanding this key step is critical for the rational design of more efficient catalysts.This review focuses on elucidating the evolution of metal-oxygen species during transition metal-catalyzed water oxidation,and more importantly,on discussing the feasible O-O bond formation mechanisms during the oxygen evolution reaction over synthetic molecular catalysts.展开更多
The formation of molecular oxygen from water by PSⅡ is supposed to occur by meansof a linear, four-electron oxidation process involving five so-called S-state intermediates（S<sub>0</sub>→S<sub>4&l...The formation of molecular oxygen from water by PSⅡ is supposed to occur by meansof a linear, four-electron oxidation process involving five so-called S-state intermediates（S<sub>0</sub>→S<sub>4</sub>）. The Mn-cluster is considered to be ligated to the PSⅡ reaction centerpolypeptides, but for its functioning, 43 and 47ku chlorophyll proteins, three peripheralproteins of 17, 23 and 33 ku need to be associated with the lumenal surface of thylakoidmembranes. These proteins, together with Ca<sup>2+</sup> and Cl<sup>-</sup>, play a regulatory role in the effi-展开更多
The influence of digalactosyldiacylglycerol (DGDG), one of the photosynthetic membrane lipids, on heat inactivation of the process of oxygen evolution has been studied in vitro in photosystem Ⅱ(PS Ⅱ) core complex. I...The influence of digalactosyldiacylglycerol (DGDG), one of the photosynthetic membrane lipids, on heat inactivation of the process of oxygen evolution has been studied in vitro in photosystem Ⅱ(PS Ⅱ) core complex. It was found that the temperature of semi-inactivation of oxygen evolution in the complex increased from 40.0 to about 43.0℃ in the presence of DGDG with 5-min heat treatment in the dark. Furthermore, when PS Ⅱ core complex was incubated for 5 min at 45.0℃, the oxygen evolution in the complex was completely lost, whilst the DGDG-complexed PS Ⅱ core complex still retained a 16% of activity (100% for 25.0℃). In addition, a 1-h incubation at 38.0℃ inactivated absolutely the oxygen evolution for the PS Ⅱ core complex. By contrast, there remained about 20% of activity (zero time for 100%) for the complex in the presence of DGDG under the same condition. These results indicate a new role of DGDG in the protection of PS Ⅱ core complex against the deleterious effects of temperature. It was展开更多
The techniques of oxygen electrode polarography and Fourier transform infrared (FT IR) spectroscopy were employed to explore the involvement of digalactosyl diacylglycerol (DGDG) in functional and structural roles in...The techniques of oxygen electrode polarography and Fourier transform infrared (FT IR) spectroscopy were employed to explore the involvement of digalactosyl diacylglycerol (DGDG) in functional and structural roles in the photosystem II core complex (PSIICC). It was shown that DGDG exhibited the ability to stimulate the oxygen evolution in PSIICC, which was accompanied by the changes in the structures of PSIICC proteins. The results revealed that there existed hydrogen bonding interactions between DGDG molecules and PSIICC proteins. It is most likely that the sites of PSIICC interaction with DGDG are in the extrinsic protein of 33 kDa.展开更多
基金State Key Basic Research Development Plan (Grant No. G1998010100) and the National Natural Science Foundation of China (Grant No. 39770156).
文摘Effects of Photosystem Ⅱ (PS Ⅱ) extrinsic polypeptides of oxygen-evolving complex and manganese clusters on PS Ⅱ carbonic anhydrase (CA) were studied with spinach PS Ⅱ membranes. The result supported that membrane-bound CA is located in the donor side of PS Ⅱ. The extrinsic polypeptides played an important role of maintaining CA activity. After removing manganese clusters, oxygen evolution activity was inhibited, but PSⅡ-CA activity was unchanged. It was concluded that CA activity is independent of the presence of manganese clusters, and was not directly correlated with oxygen evolution activity.
文摘Water oxidation is one of the most important reactions in natural and artificial energy conversion schemes.In nature,solar energy is converted to chemical energy via water oxidation at the oxygen-evolving center of photosystem II to generate dioxygen,protons,and electrons.In artificial energy schemes,water oxidation is one of the half reactions of water splitting,which is an appealing strategy for energy conversion via photocatalytic,electrocatalytic,or photoelectrocatalytic processes.Because it is thermodynamically unfavorable and kinetically slow,water oxidation is the bottleneck for achieving large-scale water splitting.Thus,developing highly efficient water oxidation catalysts has attracted the interests of researchers in the past decades.The formation of O-O bonds is typically the rate-determining step of the water oxidation catalytic cycle.Therefore,better understanding this key step is critical for the rational design of more efficient catalysts.This review focuses on elucidating the evolution of metal-oxygen species during transition metal-catalyzed water oxidation,and more importantly,on discussing the feasible O-O bond formation mechanisms during the oxygen evolution reaction over synthetic molecular catalysts.
基金Project supported by the National Natural Science Foundation of China.
文摘The formation of molecular oxygen from water by PSⅡ is supposed to occur by meansof a linear, four-electron oxidation process involving five so-called S-state intermediates（S<sub>0</sub>→S<sub>4</sub>）. The Mn-cluster is considered to be ligated to the PSⅡ reaction centerpolypeptides, but for its functioning, 43 and 47ku chlorophyll proteins, three peripheralproteins of 17, 23 and 33 ku need to be associated with the lumenal surface of thylakoidmembranes. These proteins, together with Ca<sup>2+</sup> and Cl<sup>-</sup>, play a regulatory role in the effi-
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39890390)the State Basic Research Development Plan of China (Grant No. G1998010100)the Innovative Foundation of Laboratory of Photosynthesis Basic Research, In
文摘The influence of digalactosyldiacylglycerol (DGDG), one of the photosynthetic membrane lipids, on heat inactivation of the process of oxygen evolution has been studied in vitro in photosystem Ⅱ(PS Ⅱ) core complex. It was found that the temperature of semi-inactivation of oxygen evolution in the complex increased from 40.0 to about 43.0℃ in the presence of DGDG with 5-min heat treatment in the dark. Furthermore, when PS Ⅱ core complex was incubated for 5 min at 45.0℃, the oxygen evolution in the complex was completely lost, whilst the DGDG-complexed PS Ⅱ core complex still retained a 16% of activity (100% for 25.0℃). In addition, a 1-h incubation at 38.0℃ inactivated absolutely the oxygen evolution for the PS Ⅱ core complex. By contrast, there remained about 20% of activity (zero time for 100%) for the complex in the presence of DGDG under the same condition. These results indicate a new role of DGDG in the protection of PS Ⅱ core complex against the deleterious effects of temperature. It was
文摘The techniques of oxygen electrode polarography and Fourier transform infrared (FT IR) spectroscopy were employed to explore the involvement of digalactosyl diacylglycerol (DGDG) in functional and structural roles in the photosystem II core complex (PSIICC). It was shown that DGDG exhibited the ability to stimulate the oxygen evolution in PSIICC, which was accompanied by the changes in the structures of PSIICC proteins. The results revealed that there existed hydrogen bonding interactions between DGDG molecules and PSIICC proteins. It is most likely that the sites of PSIICC interaction with DGDG are in the extrinsic protein of 33 kDa.
