[Objective]The α subunit gene of phycobiliprotein from Spirulina maxima was studied in order to provide a basis for the subsequent study of phycobiliprotein.[Method] Amino acids composition,signal peptides,hydrophobi...[Objective]The α subunit gene of phycobiliprotein from Spirulina maxima was studied in order to provide a basis for the subsequent study of phycobiliprotein.[Method] Amino acids composition,signal peptides,hydrophobicity/hydrophilicity and trails-membrane topological structure of α subunit gene of phycobiliprotein from Spirulina maxima which registered in GenBank（GenBank AF441177） were analyzed and predicted by the tools of bioinformatic analysis.Meanwhile,phylogenetic tree was constructed based on α subunit gene of phycobiliprotein from Spirulina maxima,and its molecular evolution was also analyzed.[Result]The phycobiliprotein was rich in amino acids,which not only contained 18 kinds of essential amino acids,but also contained some non-essential amino acids like glycine,aspartic acid,etc.;Analysis on signal peptides and trails-membrane topological structure showed that the phycobiliprotein belonged to intracellular protein;Analysis on hydrophobicity/hydrophilicity showed that the phycobiliprotein belonged to hydrophilic protein;Phylogenetic analysis showed that the phycobiliprotein had a high homology with Arthrospira,which reached 99%-100%.[Conclusion]The study provided a certain reference for studying the relationship and interaction between α subunit and β subunit.展开更多
An obligatory sunlight requirement for photosynthesis has exposed cyanobacteria to different quantity and quality of light. Cyanobacteria can exhibit efficient photosynthesis over broad region(450 to 650 nm) of solar ...An obligatory sunlight requirement for photosynthesis has exposed cyanobacteria to different quantity and quality of light. Cyanobacteria can exhibit efficient photosynthesis over broad region(450 to 650 nm) of solar spectrum with the help of brilliantly coloured pigment proteins called phycobiliproteins(PBPs). Besides light-harvesting, PBPs are found to involve in several life sustaining phenomena including photoprotection in cyanobacteria. The unique spectral features(like strong absorbance and fluorescence), proteineous nature and, some imperative properties like hepato-protective, antioxidants, anti-inflammatory and anti-aging activity of PBPs enable their use in food, cosmetics, pharmaceutical and biomedical industries. PBPs have been also noted to show beneficial effect in therapeutics of some disease like Alzheimer and cancer. Such large range of applications increases the demand of PBPs in commodity market. Therefore, the large-scale and coast effective production of PBPs is the real need of time. To fulfil this need, many researchers have been working to find the potential producer of PBPs for the production and purification of PBPs. Results of these efforts have caused the inventions of some novel techniques like mixotrophic and heterotrophic strategies for production and aqueous two phase separation for purification purpose. Overall, the present review summarises the recent findings and identifies gaps in the field of production, purification and applications of this biological and economically important proteins.展开更多
The excitation energy transfer from phycobiliproteins to thylakoid PSII of higher plants was investigated. When incubated with spinach thylakoids, phycobiliproteins isolated from red and blue- green algae transferred ...The excitation energy transfer from phycobiliproteins to thylakoid PSII of higher plants was investigated. When incubated with spinach thylakoids, phycobiliproteins isolated from red and blue- green algae transferred light energy absorbed to spinach PSII. The efficiency of energy transfer was dependent on the kind of phycobiliproteins used. If spinach thylakoids were replaced by the thylakoids of Brassica chinensis, R phycoerythin or C- phycocyanin did not transfer their excitation energy to PSII of Brassica chinensis unless allophycocyanin was present.展开更多
The Synechocystis sp. PCC 6803 genome harbours a Deg gene family consisting of three members, htrA （degP, slr1204）, hhoA （degQ, sll1679） and hhoB （degS, sll1427）. This work provided biochemical characterization ...The Synechocystis sp. PCC 6803 genome harbours a Deg gene family consisting of three members, htrA （degP, slr1204）, hhoA （degQ, sll1679） and hhoB （degS, sll1427）. This work provided biochemical characterization of HhoA, HtrA and HhoB from Synechocystis sp. PCC 6803. Firstly mature HhoA, HhoB and HtrA from Synechocystis sp. PCC 6803 were cloned and expressed as soluble recombinant his-tagged fusion protein in Escherichia coli. Then the proteolytic activity of HhoA, HhoB and HtrA was tested using casein, bovine serum albumin, five recombinant chromoproteins and cyanobacterial phycocyanin as substrates in vitro. The experimental results showed that HhoA and HtrA had proteolytic activity on casein, five recombinant chromoproteins and cyanobacterial phycocyanin. No proteolytic activity of HhoB was found using all substrates in vitro, indicating functional difference among Deg proteases from Synechocystis sp. PCC 6803. Therefore, the results indicated the biochemical properties of HhoA and HtrA on hydrolysis of proteins and phycobiliproteins in vitro, which implicated that they were proteases possibly involved in phycobiliprotein degradation in vivo.展开更多
Cyanobacteria are considered as a sustainable feedstock for the production of biochemically active compounds such as phycobiliproteins(PBPs).In this study,the impact of nitrogen(N)and phosphorus(P)availability on PBP ...Cyanobacteria are considered as a sustainable feedstock for the production of biochemically active compounds such as phycobiliproteins(PBPs).In this study,the impact of nitrogen(N)and phosphorus(P)availability on PBP production of“N-free acclimated”Anabaena variabilis IMU8 was analyzed.Upon isolation and identification,the cyanobacterium has been maintained in N-free BG-11 medium for more than 20 months.For experimentation,the strain was incubated in N-replete,N-depleted,N-P-depleted BG-11 medium.Long-term diazotrophic cultivation of A.variabilis IMU8 resulted in elevated PBP productivity with a limited impact on growth.When compared to N-depleted ones,N supply stimulated a slight induction of growth and total saccharide production,but total protein content did not change while PBP production decreased.On the other hand,N-P-depletion resulted in decreased growth rate along with reduced total protein and PBP production while rapid induction of total saccharide production was recorded.Fourier transform infrared spectroscopy results refer that membrane-bound oligosaccharides may have regulatory roles for PBP production in A.variabilis IMU8 during long term diazotrophic cultivation.展开更多
A discrete model was used for studying the effects of exciton annihilation on the decay behavior of the excited state in phycobiliprotein super-molecules. The simulation shows: The more the chromophores are and the hi...A discrete model was used for studying the effects of exciton annihilation on the decay behavior of the excited state in phycobiliprotein super-molecules. The simulation shows: The more the chromophores are and the higher the excitation beam intensity is, the more susceptible to annihilation is a system; annihilation starts to occur at 10^(13) photons/cm^2 and becomes saturated at about 10^(15)—10^(16) photons/cm^2 with the parameters used in the current work. Whether the exciton annihilation occurs or not should not be simply judged from whether the decaying data could be fitted with a mono-exponential function. The quantum yield of fluorescence decreases synchronously with the increase of exciton annihilation extent. The so called 'safety intensity' has significance only in special cases. In fact, annihilation extent is dependent not only on the pulse intensity but also on the width of the pulse, the optical cross section of a chromophore as well as the light absorption coefficient of a system.展开更多
Scavenging of hydroxyl radical (·OH) by phycobiliproteins (C-phycocyanin, Allophyco- cyanin and R-phycoerythrin) was studied by competitive kinetics methods. Hydroxyl radicals were generated from pulse radiolysis...Scavenging of hydroxyl radical (·OH) by phycobiliproteins (C-phycocyanin, Allophyco- cyanin and R-phycoerythrin) was studied by competitive kinetics methods. Hydroxyl radicals were generated from pulse radiolysis of aqueous systems saturated with nitrous oxide (N2O). The experimental results indicated that the three types of phycobiliproteins are all strong scavengers of· OH, the rate constants are around (2.8-5.6)×109 L·2 mol1 · s 1.展开更多
Glycine betaine(GB) is a biologically important small molecule protecting cells,proteins and enzymes in vivo and in vitro under environmental stresses.Recently,it was found that GB could also relax the structure and i...Glycine betaine(GB) is a biologically important small molecule protecting cells,proteins and enzymes in vivo and in vitro under environmental stresses.Recently,it was found that GB could also relax the structure and inactivate the function of phycobiliproteins and phycobilisome(PBS),a kind of supramolecular complexes,in cyanobacterial cells.The molecular mechanisms for the opposite phenomena are quite ambiguous.Taking PBS and a trimeric or monomeric C-phycocyanin(C-PC) as models,the molecular mechanism for the interaction of GB with supra-molecular complexes or nuclear proteins was investigated.The energetic decoupling of PBS components induced by GB suggests that the PBS core-membrane linking polypeptide was the most sensitive site while the rod-core linker was the next.Biochemistry analysis proves that PBS structure was loosened but not dissociated into the components.On the basis of the results and structure knowledge,it was proposed that GB screened the electrostatic attraction of the opposite charges on a linker and a protein leading to a much looser structure.It was observed that GB induced a spectral blue shift for trimeric C-PC but a red shift for a monomeric C-PC(a nuclear protein),which were ascribed to GB's screening of the electrostatic attraction of a linker to a protein and strengthening of the hydrophobic interaction between C-PC monomers.The trimers and monomers' forming of the same products under high concentration of GB was ascribed to a compromise of the opposite interaction forces.展开更多
基金Supported by the Special Project for Public-welfare Industry of Chinese Forestry (200704025) The Key Project of Chinese Ministry of Education (102023)~~
文摘[Objective]The α subunit gene of phycobiliprotein from Spirulina maxima was studied in order to provide a basis for the subsequent study of phycobiliprotein.[Method] Amino acids composition,signal peptides,hydrophobicity/hydrophilicity and trails-membrane topological structure of α subunit gene of phycobiliprotein from Spirulina maxima which registered in GenBank（GenBank AF441177） were analyzed and predicted by the tools of bioinformatic analysis.Meanwhile,phylogenetic tree was constructed based on α subunit gene of phycobiliprotein from Spirulina maxima,and its molecular evolution was also analyzed.[Result]The phycobiliprotein was rich in amino acids,which not only contained 18 kinds of essential amino acids,but also contained some non-essential amino acids like glycine,aspartic acid,etc.;Analysis on signal peptides and trails-membrane topological structure showed that the phycobiliprotein belonged to intracellular protein;Analysis on hydrophobicity/hydrophilicity showed that the phycobiliprotein belonged to hydrophilic protein;Phylogenetic analysis showed that the phycobiliprotein had a high homology with Arthrospira,which reached 99%-100%.[Conclusion]The study provided a certain reference for studying the relationship and interaction between α subunit and β subunit.
基金Department of Science and Technology,New Delhi,India for financial help in the form of the INSPIRE (IF120712) fellowshipUniversity Grant Commission,New Delhi,India for Dr.Kothari DS Post- doctoral Research Grant
文摘An obligatory sunlight requirement for photosynthesis has exposed cyanobacteria to different quantity and quality of light. Cyanobacteria can exhibit efficient photosynthesis over broad region(450 to 650 nm) of solar spectrum with the help of brilliantly coloured pigment proteins called phycobiliproteins(PBPs). Besides light-harvesting, PBPs are found to involve in several life sustaining phenomena including photoprotection in cyanobacteria. The unique spectral features(like strong absorbance and fluorescence), proteineous nature and, some imperative properties like hepato-protective, antioxidants, anti-inflammatory and anti-aging activity of PBPs enable their use in food, cosmetics, pharmaceutical and biomedical industries. PBPs have been also noted to show beneficial effect in therapeutics of some disease like Alzheimer and cancer. Such large range of applications increases the demand of PBPs in commodity market. Therefore, the large-scale and coast effective production of PBPs is the real need of time. To fulfil this need, many researchers have been working to find the potential producer of PBPs for the production and purification of PBPs. Results of these efforts have caused the inventions of some novel techniques like mixotrophic and heterotrophic strategies for production and aqueous two phase separation for purification purpose. Overall, the present review summarises the recent findings and identifies gaps in the field of production, purification and applications of this biological and economically important proteins.
文摘The excitation energy transfer from phycobiliproteins to thylakoid PSII of higher plants was investigated. When incubated with spinach thylakoids, phycobiliproteins isolated from red and blue- green algae transferred light energy absorbed to spinach PSII. The efficiency of energy transfer was dependent on the kind of phycobiliproteins used. If spinach thylakoids were replaced by the thylakoids of Brassica chinensis, R phycoerythin or C- phycocyanin did not transfer their excitation energy to PSII of Brassica chinensis unless allophycocyanin was present.
基金Funded by the National Natural Science Foundation of China (Nos.30870541,30870519)
文摘The Synechocystis sp. PCC 6803 genome harbours a Deg gene family consisting of three members, htrA （degP, slr1204）, hhoA （degQ, sll1679） and hhoB （degS, sll1427）. This work provided biochemical characterization of HhoA, HtrA and HhoB from Synechocystis sp. PCC 6803. Firstly mature HhoA, HhoB and HtrA from Synechocystis sp. PCC 6803 were cloned and expressed as soluble recombinant his-tagged fusion protein in Escherichia coli. Then the proteolytic activity of HhoA, HhoB and HtrA was tested using casein, bovine serum albumin, five recombinant chromoproteins and cyanobacterial phycocyanin as substrates in vitro. The experimental results showed that HhoA and HtrA had proteolytic activity on casein, five recombinant chromoproteins and cyanobacterial phycocyanin. No proteolytic activity of HhoB was found using all substrates in vitro, indicating functional difference among Deg proteases from Synechocystis sp. PCC 6803. Therefore, the results indicated the biochemical properties of HhoA and HtrA on hydrolysis of proteins and phycobiliproteins in vitro, which implicated that they were proteases possibly involved in phycobiliprotein degradation in vivo.
基金funded by the Turkish Ministry of Agriculture and Forestry General Directorate of Agricultural Research,grant number TAGEM-12/AR-GE/13.
文摘Cyanobacteria are considered as a sustainable feedstock for the production of biochemically active compounds such as phycobiliproteins(PBPs).In this study,the impact of nitrogen(N)and phosphorus(P)availability on PBP production of“N-free acclimated”Anabaena variabilis IMU8 was analyzed.Upon isolation and identification,the cyanobacterium has been maintained in N-free BG-11 medium for more than 20 months.For experimentation,the strain was incubated in N-replete,N-depleted,N-P-depleted BG-11 medium.Long-term diazotrophic cultivation of A.variabilis IMU8 resulted in elevated PBP productivity with a limited impact on growth.When compared to N-depleted ones,N supply stimulated a slight induction of growth and total saccharide production,but total protein content did not change while PBP production decreased.On the other hand,N-P-depletion resulted in decreased growth rate along with reduced total protein and PBP production while rapid induction of total saccharide production was recorded.Fourier transform infrared spectroscopy results refer that membrane-bound oligosaccharides may have regulatory roles for PBP production in A.variabilis IMU8 during long term diazotrophic cultivation.
文摘A discrete model was used for studying the effects of exciton annihilation on the decay behavior of the excited state in phycobiliprotein super-molecules. The simulation shows: The more the chromophores are and the higher the excitation beam intensity is, the more susceptible to annihilation is a system; annihilation starts to occur at 10^(13) photons/cm^2 and becomes saturated at about 10^(15)—10^(16) photons/cm^2 with the parameters used in the current work. Whether the exciton annihilation occurs or not should not be simply judged from whether the decaying data could be fitted with a mono-exponential function. The quantum yield of fluorescence decreases synchronously with the increase of exciton annihilation extent. The so called 'safety intensity' has significance only in special cases. In fact, annihilation extent is dependent not only on the pulse intensity but also on the width of the pulse, the optical cross section of a chromophore as well as the light absorption coefficient of a system.
文摘Scavenging of hydroxyl radical (·OH) by phycobiliproteins (C-phycocyanin, Allophyco- cyanin and R-phycoerythrin) was studied by competitive kinetics methods. Hydroxyl radicals were generated from pulse radiolysis of aqueous systems saturated with nitrous oxide (N2O). The experimental results indicated that the three types of phycobiliproteins are all strong scavengers of· OH, the rate constants are around (2.8-5.6)×109 L·2 mol1 · s 1.
基金Supported by the National Natural Science Foundation of China (Grant No. 20872144)
文摘Glycine betaine(GB) is a biologically important small molecule protecting cells,proteins and enzymes in vivo and in vitro under environmental stresses.Recently,it was found that GB could also relax the structure and inactivate the function of phycobiliproteins and phycobilisome(PBS),a kind of supramolecular complexes,in cyanobacterial cells.The molecular mechanisms for the opposite phenomena are quite ambiguous.Taking PBS and a trimeric or monomeric C-phycocyanin(C-PC) as models,the molecular mechanism for the interaction of GB with supra-molecular complexes or nuclear proteins was investigated.The energetic decoupling of PBS components induced by GB suggests that the PBS core-membrane linking polypeptide was the most sensitive site while the rod-core linker was the next.Biochemistry analysis proves that PBS structure was loosened but not dissociated into the components.On the basis of the results and structure knowledge,it was proposed that GB screened the electrostatic attraction of the opposite charges on a linker and a protein leading to a much looser structure.It was observed that GB induced a spectral blue shift for trimeric C-PC but a red shift for a monomeric C-PC(a nuclear protein),which were ascribed to GB's screening of the electrostatic attraction of a linker to a protein and strengthening of the hydrophobic interaction between C-PC monomers.The trimers and monomers' forming of the same products under high concentration of GB was ascribed to a compromise of the opposite interaction forces.
