Excitation energy transfer in phycoerythrocyanins (PEC) was studied by use of computer simulation. The results observed from the simulation are as follows: (i) The α84 is a more efficient sensitizing chromophore than...Excitation energy transfer in phycoerythrocyanins (PEC) was studied by use of computer simulation. The results observed from the simulation are as follows: (i) The α84 is a more efficient sensitizing chromophore than β155 and donates the excitation energy into β84 and β155 while it scarcely emits fluorescence itself, (ii) Only the 1α84 →2β84 is the sub-picosecond process in a PEC trimer, therefore it is readily to obtain the time constant from fs-level time-resolved spectral measurement. (iii) The β84 and β155 chromophores in PEC behave quite differently from those in C-PC because of the changes in α84. It is observed that 1β156→6β155 is the dominant pathway linking two trimers and both of the chromophores possess much higher fluorescence fractions, and about 80% of the total fluorescence is emitted from the β84 chromophore. (iv) A far less mean number of transfer times is observed through the fast-transfer pairs in PEC compared with that in C-PC because of slow transfer rate for the path from 2β84→1α84. (v) Relatively, PEC could absorb and transfer excitation energy more efficiently than C-PC.展开更多
By PCR method, apo phycoerythrocyanin α subunit gene (pecA) of Mastigocladus laminosus (M. laminosus) was amplified from its genomic DNA, and then cloned in pBluescript. The pecA gene was subcloned into the exp...By PCR method, apo phycoerythrocyanin α subunit gene (pecA) of Mastigocladus laminosus (M. laminosus) was amplified from its genomic DNA, and then cloned in pBluescript. The pecA gene was subcloned into the expression vector pGEMD, and then transformed into E.coli BL21 (DE3). After induction, a new protein of molecular weight 19×10 3 existing in inclusion body was overexpressed. The expressed product was confirmed to be apo phycoerythrocyanin α subunit by Dot ELISA.展开更多
The excitation energy transfer processes in trimeric PEC have been studied by using steady state and time resolved fluorescence spectra techniques in detail. The results indicate that the energy transfer processes sho...The excitation energy transfer processes in trimeric PEC have been studied by using steady state and time resolved fluorescence spectra techniques in detail. The results indicate that the energy transfer processes should take place between α 84 PVB and β 84 or β 155 PCB chromophores with the time constants 34.7 ps and 175-200 ps individually; in contrast with monomeric PEC, from time resolved fluorescence anisotropic spectrum technique, the decay constant of 45 ps which was assigned to the energy transfer time among three β 84 PCB chromophores was observed and the energy levels of β 84 and/or β 155 PCB chromophores were confirmed to turn over in trimeric PEC.展开更多
In this article,we proposed that CpcC1 and CpcC2 connect distal and middle phycocyanin discs of phycobilisomes,respectively,in Leptolyngbya sp.PCC 6406.However,Ughy and Ajlani (2004) have concluded that CpcC2 and CpcC...In this article,we proposed that CpcC1 and CpcC2 connect distal and middle phycocyanin discs of phycobilisomes,respectively,in Leptolyngbya sp.PCC 6406.However,Ughy and Ajlani (2004) have concluded that CpcC2 and CpcC1 connect distal and middle discs,respectively,based on the mutagenesis results in Synechocystis sp.PCC 6803.Therefore,we replaced the original Figure 2 with a new one containing corrected Figure 2G and corrected one sentence on page 718,"In the hemi-discoidal PBS of Synechocystis sp.PCC6803,CpcC1,CpcC2,and CpcG connect the distal,middle,and basal discs of the PC rods,respectively (Ughy and Ajlani,2004;Arteni et al.,2009)",to "In the hemi-discoidal PBS of Synechocystis sp.PCC6803,CpcC2,CpcC1,and CpcG connect the distal,middle,and basal discs of the PC rods,respectively (Ughy and Ajlani,2004;Arteni et al.,2009) This correction does not affect the conclusions of this work.展开更多
Cyanobacteria have evolved various photoacclimation processes to perform oxygenic photosynthesis under different light environments.Chromatic acclimation(CA)is a widely recognized and ecologically important type of ph...Cyanobacteria have evolved various photoacclimation processes to perform oxygenic photosynthesis under different light environments.Chromatic acclimation(CA)is a widely recognized and ecologically important type of photoacclimation,whereby cyanobacteria alter the absorbing light colors of a supermolecular antenna complex called the phycobilisome.To date,several CA variants that regulate the green-absorbing phycoerythrin(PE)and/or the red-absorbing phycocyanin(PC)within the hemi-discoidal form of phycobilisome have been characterized.In this study,we identified a unique CA regulatory gene cluster encoding yellow-green-absorbing phycoerythrocyanin(PEC)and a rod-membrane linker protein(CpcL)for the rod-shaped form of phycobilisome.Using the cyanobacterium Leptolyngbya sp.PCC 6406,we revealed novel CA variants regulating PEC(CA7)and the rod-shaped phycobilisome(CAO),which maximize yellowgreen light-harvesting capacity and balance the excitation of photosystems,respective!y.Analysis of the distribution of CA gene clusters in 445 cyanobacteria genomes revealed eight CA variants responding to green and red light,which are classified based on the presence of PEC,PE,cpcL,and CA photosensor genes.Phylogenetic analysis further suggested that the emergence of CA7 was a single event and preceded that of heterocystous strains,whereas the acquisition of CAO occurred multiple times.Taken together,these results offer novel insights into the diversity and evolution of the complex cyanobacterial photoacclimation mechanisms.展开更多
基金Project supported by the National Natural Science Foundation of China
文摘Excitation energy transfer in phycoerythrocyanins (PEC) was studied by use of computer simulation. The results observed from the simulation are as follows: (i) The α84 is a more efficient sensitizing chromophore than β155 and donates the excitation energy into β84 and β155 while it scarcely emits fluorescence itself, (ii) Only the 1α84 →2β84 is the sub-picosecond process in a PEC trimer, therefore it is readily to obtain the time constant from fs-level time-resolved spectral measurement. (iii) The β84 and β155 chromophores in PEC behave quite differently from those in C-PC because of the changes in α84. It is observed that 1β156→6β155 is the dominant pathway linking two trimers and both of the chromophores possess much higher fluorescence fractions, and about 80% of the total fluorescence is emitted from the β84 chromophore. (iv) A far less mean number of transfer times is observed through the fast-transfer pairs in PEC compared with that in C-PC because of slow transfer rate for the path from 2β84→1α84. (v) Relatively, PEC could absorb and transfer excitation energy more efficiently than C-PC.
文摘By PCR method, apo phycoerythrocyanin α subunit gene (pecA) of Mastigocladus laminosus (M. laminosus) was amplified from its genomic DNA, and then cloned in pBluescript. The pecA gene was subcloned into the expression vector pGEMD, and then transformed into E.coli BL21 (DE3). After induction, a new protein of molecular weight 19×10 3 existing in inclusion body was overexpressed. The expressed product was confirmed to be apo phycoerythrocyanin α subunit by Dot ELISA.
文摘The excitation energy transfer processes in trimeric PEC have been studied by using steady state and time resolved fluorescence spectra techniques in detail. The results indicate that the energy transfer processes should take place between α 84 PVB and β 84 or β 155 PCB chromophores with the time constants 34.7 ps and 175-200 ps individually; in contrast with monomeric PEC, from time resolved fluorescence anisotropic spectrum technique, the decay constant of 45 ps which was assigned to the energy transfer time among three β 84 PCB chromophores was observed and the energy levels of β 84 and/or β 155 PCB chromophores were confirmed to turn over in trimeric PEC.
文摘In this article,we proposed that CpcC1 and CpcC2 connect distal and middle phycocyanin discs of phycobilisomes,respectively,in Leptolyngbya sp.PCC 6406.However,Ughy and Ajlani (2004) have concluded that CpcC2 and CpcC1 connect distal and middle discs,respectively,based on the mutagenesis results in Synechocystis sp.PCC 6803.Therefore,we replaced the original Figure 2 with a new one containing corrected Figure 2G and corrected one sentence on page 718,"In the hemi-discoidal PBS of Synechocystis sp.PCC6803,CpcC1,CpcC2,and CpcG connect the distal,middle,and basal discs of the PC rods,respectively (Ughy and Ajlani,2004;Arteni et al.,2009)",to "In the hemi-discoidal PBS of Synechocystis sp.PCC6803,CpcC2,CpcC1,and CpcG connect the distal,middle,and basal discs of the PC rods,respectively (Ughy and Ajlani,2004;Arteni et al.,2009) This correction does not affect the conclusions of this work.
基金a Grant-in-Aid for Young Scientists(B)(no.25830130)a Grant-in-Aid for Challenging Exploratory Research(no.15K14486)+1 种基金a Grant-in-Aid for Young Scientists(A)(no.15H05578)from the Japan Society for the Promotion of Science(to Y.H.).This work was also supported by the Cooperative Study Program of the National Institute for Physiological Sciences(to Y.H.)by the BIO-NEXT project of ExCELLS and the Functional Genomics Facility of the National Institute for Basic Biology.This work was also supported by the Naito Foundation,Tatematsu Foundation,Yazaki Memorial Foundation,and Takeda Science Foundation(to Y.H.).
文摘Cyanobacteria have evolved various photoacclimation processes to perform oxygenic photosynthesis under different light environments.Chromatic acclimation(CA)is a widely recognized and ecologically important type of photoacclimation,whereby cyanobacteria alter the absorbing light colors of a supermolecular antenna complex called the phycobilisome.To date,several CA variants that regulate the green-absorbing phycoerythrin(PE)and/or the red-absorbing phycocyanin(PC)within the hemi-discoidal form of phycobilisome have been characterized.In this study,we identified a unique CA regulatory gene cluster encoding yellow-green-absorbing phycoerythrocyanin(PEC)and a rod-membrane linker protein(CpcL)for the rod-shaped form of phycobilisome.Using the cyanobacterium Leptolyngbya sp.PCC 6406,we revealed novel CA variants regulating PEC(CA7)and the rod-shaped phycobilisome(CAO),which maximize yellowgreen light-harvesting capacity and balance the excitation of photosystems,respective!y.Analysis of the distribution of CA gene clusters in 445 cyanobacteria genomes revealed eight CA variants responding to green and red light,which are classified based on the presence of PEC,PE,cpcL,and CA photosensor genes.Phylogenetic analysis further suggested that the emergence of CA7 was a single event and preceded that of heterocystous strains,whereas the acquisition of CAO occurred multiple times.Taken together,these results offer novel insights into the diversity and evolution of the complex cyanobacterial photoacclimation mechanisms.
