The Experts below are selected from a list of 14037 Experts worldwide ranked by ideXlab platform
Kaihong Zhao - One of the best experts on this subject based on the ideXlab platform.
-
chromophorylation in escherichia coli of Allophycocyanin b subunits from far red light acclimated chroococcidiopsis thermalis sp pcc7203
Photochemical and Photobiological Sciences, 2017Co-Authors: Qianzhao Xu, Qiying Tang, Wenlong Ding, Baoqing Zhao, Ming Zhou, Wolfgang Gartner, Hugo Scheer, Kaihong ZhaoAbstract:Cyanobacterial phycobilisomes funnel the harvested light energy to the reaction centers via two terminal emitters, Allophycocyanin B and the core–membrane linker. ApcD is the α-subunit of Allophycocyanin B responsible for its red-shifted absorbance (λmax 665 nm). Far-red photo-acclimated cyanobacteria contain certain Allophycocyanins that show even further red-shifted absorbances (λmax > 700 nm). We studied the chromophorylation of the three far-red induced ApcD subunits ApcD2, ApcD3 and ApcD4 from Chroococcidiopsis thermalis sp. PCC7203 during the expression in E. coli. The complex behavior emphasizes that a variety of factors contribute to the spectral red-shift. Only ApcD2 bound phycocyanobilin covalently at the canonical position C81, while ApcD3 and ApcD4 gave only traces of stable products. The product of ApcD2 was, however, heterogeneous. The major fraction had a broad absorption around 560 nm and double-peaked fluorescence at 615 and 670 nm. A minor fraction was similar to the product of conventional ApcD, with maximal absorbance around 610 nm and fluorescence around 640 nm. The heterogeneity was lost in C65 and C132 variants; in these variants only the conventional product was formed. With ApcD4, a red-shifted product carrying non-covalently bound phycocyanobilin could be detected in the supernatant after cell lysis. While this chromophore was lost during purification, it could be stabilized by co-assembly with a far-red light-induced β-subunit, ApcB3.
-
chromophorylation in escherichia coli of Allophycocyanin b subunits from far red light acclimated chroococcidiopsis thermalis sp pcc7203
Photochemical and Photobiological Sciences, 2017Co-Authors: Qiying Tang, Wenlong Ding, Baoqing Zhao, Ming Zhou, Wolfgang Gartner, Hugo Scheer, Jiaxin Han, Kaihong ZhaoAbstract:Cyanobacterial phycobilisomes funnel the harvested light energy to the reaction centers via two terminal emitters, Allophycocyanin B and the core-membrane linker. ApcD is the α-subunit of Allophycocyanin B responsible for its red-shifted absorbance (λmax 665 nm). Far-red photo-acclimated cyanobacteria contain certain Allophycocyanins that show even further red-shifted absorbances (λmax > 700 nm). We studied the chromophorylation of the three far-red induced ApcD subunits ApcD2, ApcD3 and ApcD4 from Chroococcidiopsis thermalis sp. PCC7203 during the expression in E. coli. The complex behavior emphasizes that a variety of factors contribute to the spectral red-shift. Only ApcD2 bound phycocyanobilin covalently at the canonical position C81, while ApcD3 and ApcD4 gave only traces of stable products. The product of ApcD2 was, however, heterogeneous. The major fraction had a broad absorption around 560 nm and double-peaked fluorescence at 615 and 670 nm. A minor fraction was similar to the product of conventional ApcD, with maximal absorbance around 610 nm and fluorescence around 640 nm. The heterogeneity was lost in C65 and C132 variants; in these variants only the conventional product was formed. With ApcD4, a red-shifted product carrying non-covalently bound phycocyanobilin could be detected in the supernatant after cell lysis. While this chromophore was lost during purification, it could be stabilized by co-assembly with a far-red light-induced β-subunit, ApcB3.
-
RESONANCE‐ENHANCED CARS SPECTROSCOPY OF BILIPROTEINS. INFLUENCE OF AGGREGATION and LINKER PROTEINS ON CHROMOPHORE STRUCTURE IN Allophycocyanin (Mastigocladus laminosus)
Photochemistry and Photobiology, 2008Co-Authors: Siegfried Schneider, Kaihong Zhao, C. J. Prenzel, G. Brehm, Lothar Gottschalk, Hugo ScheerAbstract:— Resonance-enhanced coherent anti-Stokes Raman spectra (CARS) are reported for monomers and for trimers with and without linker proteins of Allophycocyanin isolated from Mastigocladus laminosus. The CARS spectrum of the monomer is independent of the presence of linker proteins and is very similar to that of phycocyanin monomers indicating that the equivalent chromophores exhibit like structures in both biliproteins. Large differences are, however, observed between the spectra of phycocyanin trimers and those of Allophycocyanin trimers with or without linker proteins (Lc8,9). The observed differences between monomer and trimer spectra are consistent with a change of the α-chromophore-protein arrangement upon aggregation without linker. If linker proteins are present in the trimer, then additional geometry changes of the β-chromophores are induced; these could relate to a transition from the 15Z-anti to 15Z-syn conformation.
-
resonance enhanced cars spectroscopy of biliproteins influence of aggregation and linker proteins on chromophore structure in Allophycocyanin mastigocladus laminosus
Photochemistry and Photobiology, 2008Co-Authors: Siegfried Schneider, Kaihong Zhao, C. J. Prenzel, G. Brehm, Lothar Gottschalk, Hugo ScheerAbstract:— Resonance-enhanced coherent anti-Stokes Raman spectra (CARS) are reported for monomers and for trimers with and without linker proteins of Allophycocyanin isolated from Mastigocladus laminosus. The CARS spectrum of the monomer is independent of the presence of linker proteins and is very similar to that of phycocyanin monomers indicating that the equivalent chromophores exhibit like structures in both biliproteins. Large differences are, however, observed between the spectra of phycocyanin trimers and those of Allophycocyanin trimers with or without linker proteins (Lc8,9). The observed differences between monomer and trimer spectra are consistent with a change of the α-chromophore-protein arrangement upon aggregation without linker. If linker proteins are present in the trimer, then additional geometry changes of the β-chromophores are induced; these could relate to a transition from the 15Z-anti to 15Z-syn conformation.
Hugo Scheer - One of the best experts on this subject based on the ideXlab platform.
-
chromophorylation in escherichia coli of Allophycocyanin b subunits from far red light acclimated chroococcidiopsis thermalis sp pcc7203
Photochemical and Photobiological Sciences, 2017Co-Authors: Qianzhao Xu, Qiying Tang, Wenlong Ding, Baoqing Zhao, Ming Zhou, Wolfgang Gartner, Hugo Scheer, Kaihong ZhaoAbstract:Cyanobacterial phycobilisomes funnel the harvested light energy to the reaction centers via two terminal emitters, Allophycocyanin B and the core–membrane linker. ApcD is the α-subunit of Allophycocyanin B responsible for its red-shifted absorbance (λmax 665 nm). Far-red photo-acclimated cyanobacteria contain certain Allophycocyanins that show even further red-shifted absorbances (λmax > 700 nm). We studied the chromophorylation of the three far-red induced ApcD subunits ApcD2, ApcD3 and ApcD4 from Chroococcidiopsis thermalis sp. PCC7203 during the expression in E. coli. The complex behavior emphasizes that a variety of factors contribute to the spectral red-shift. Only ApcD2 bound phycocyanobilin covalently at the canonical position C81, while ApcD3 and ApcD4 gave only traces of stable products. The product of ApcD2 was, however, heterogeneous. The major fraction had a broad absorption around 560 nm and double-peaked fluorescence at 615 and 670 nm. A minor fraction was similar to the product of conventional ApcD, with maximal absorbance around 610 nm and fluorescence around 640 nm. The heterogeneity was lost in C65 and C132 variants; in these variants only the conventional product was formed. With ApcD4, a red-shifted product carrying non-covalently bound phycocyanobilin could be detected in the supernatant after cell lysis. While this chromophore was lost during purification, it could be stabilized by co-assembly with a far-red light-induced β-subunit, ApcB3.
-
chromophorylation in escherichia coli of Allophycocyanin b subunits from far red light acclimated chroococcidiopsis thermalis sp pcc7203
Photochemical and Photobiological Sciences, 2017Co-Authors: Qiying Tang, Wenlong Ding, Baoqing Zhao, Ming Zhou, Wolfgang Gartner, Hugo Scheer, Jiaxin Han, Kaihong ZhaoAbstract:Cyanobacterial phycobilisomes funnel the harvested light energy to the reaction centers via two terminal emitters, Allophycocyanin B and the core-membrane linker. ApcD is the α-subunit of Allophycocyanin B responsible for its red-shifted absorbance (λmax 665 nm). Far-red photo-acclimated cyanobacteria contain certain Allophycocyanins that show even further red-shifted absorbances (λmax > 700 nm). We studied the chromophorylation of the three far-red induced ApcD subunits ApcD2, ApcD3 and ApcD4 from Chroococcidiopsis thermalis sp. PCC7203 during the expression in E. coli. The complex behavior emphasizes that a variety of factors contribute to the spectral red-shift. Only ApcD2 bound phycocyanobilin covalently at the canonical position C81, while ApcD3 and ApcD4 gave only traces of stable products. The product of ApcD2 was, however, heterogeneous. The major fraction had a broad absorption around 560 nm and double-peaked fluorescence at 615 and 670 nm. A minor fraction was similar to the product of conventional ApcD, with maximal absorbance around 610 nm and fluorescence around 640 nm. The heterogeneity was lost in C65 and C132 variants; in these variants only the conventional product was formed. With ApcD4, a red-shifted product carrying non-covalently bound phycocyanobilin could be detected in the supernatant after cell lysis. While this chromophore was lost during purification, it could be stabilized by co-assembly with a far-red light-induced β-subunit, ApcB3.
-
RESONANCE‐ENHANCED CARS SPECTROSCOPY OF BILIPROTEINS. INFLUENCE OF AGGREGATION and LINKER PROTEINS ON CHROMOPHORE STRUCTURE IN Allophycocyanin (Mastigocladus laminosus)
Photochemistry and Photobiology, 2008Co-Authors: Siegfried Schneider, Kaihong Zhao, C. J. Prenzel, G. Brehm, Lothar Gottschalk, Hugo ScheerAbstract:— Resonance-enhanced coherent anti-Stokes Raman spectra (CARS) are reported for monomers and for trimers with and without linker proteins of Allophycocyanin isolated from Mastigocladus laminosus. The CARS spectrum of the monomer is independent of the presence of linker proteins and is very similar to that of phycocyanin monomers indicating that the equivalent chromophores exhibit like structures in both biliproteins. Large differences are, however, observed between the spectra of phycocyanin trimers and those of Allophycocyanin trimers with or without linker proteins (Lc8,9). The observed differences between monomer and trimer spectra are consistent with a change of the α-chromophore-protein arrangement upon aggregation without linker. If linker proteins are present in the trimer, then additional geometry changes of the β-chromophores are induced; these could relate to a transition from the 15Z-anti to 15Z-syn conformation.
-
resonance enhanced cars spectroscopy of biliproteins influence of aggregation and linker proteins on chromophore structure in Allophycocyanin mastigocladus laminosus
Photochemistry and Photobiology, 2008Co-Authors: Siegfried Schneider, Kaihong Zhao, C. J. Prenzel, G. Brehm, Lothar Gottschalk, Hugo ScheerAbstract:— Resonance-enhanced coherent anti-Stokes Raman spectra (CARS) are reported for monomers and for trimers with and without linker proteins of Allophycocyanin isolated from Mastigocladus laminosus. The CARS spectrum of the monomer is independent of the presence of linker proteins and is very similar to that of phycocyanin monomers indicating that the equivalent chromophores exhibit like structures in both biliproteins. Large differences are, however, observed between the spectra of phycocyanin trimers and those of Allophycocyanin trimers with or without linker proteins (Lc8,9). The observed differences between monomer and trimer spectra are consistent with a change of the α-chromophore-protein arrangement upon aggregation without linker. If linker proteins are present in the trimer, then additional geometry changes of the β-chromophores are induced; these could relate to a transition from the 15Z-anti to 15Z-syn conformation.
Sashka Krumova - One of the best experts on this subject based on the ideXlab platform.
-
Structural integrity of Synechocystis sp. PCC 6803 phycobilisomes evaluated by means of differential scanning calorimetry
Photosynthesis Research, 2018Co-Authors: Nia Petrova, Hajnalka Laczko-dobos, Tomas Zakar, Stefka Taneva, Zoltán Gombos, Sindhujaa Vajravel, Svetla Todinova, Sashka KrumovaAbstract:Phycobilisomes (PBSs) are supramolecular pigment–protein complexes that serve as light-harvesting antennae in cyanobacteria. They are built up by phycobiliproteins assembled into Allophycocyanin core cylinders (ensuring the physical interaction with the photosystems) and phycocyanin rods (protruding from the cores and having light-harvesting function), the whole PBSs structure being maintained by linker proteins. PBSs play major role in light-harvesting optimization in cyanobacteria; therefore, the characterization of their structural integrity in intact cells is of great importance. The present study utilizes differential scanning calorimetry and spectroscopy techniques to explore for the first time, the thermodynamic stability of PBSs in intact Synechocystis sp. PCC 6803 cells and to probe its alteration as a result of mutations or under different growth conditions. As a first step, we characterize the thermodynamic behavior of intact and dismantled PBSs isolated from wild-type cells (having fully assembled PBSs) and from CK mutant cells (that lack phycocyanin rods and contain only Allophycocyanin cores), and identified the thermal transitions of phycocyanin and Allophycocyanin units in vitro. Next, we demonstrate that in intact cells PBSs exhibit sharp, high amplitude thermal transition at about 63 °C that strongly depends on the structural integrity of the PBSs supercomplex. Our findings implicate that calorimetry could offer a valuable approach for the assessment of the influence of variety of factors affecting the stability and structural organization of phycobilisomes in intact cyanobacterial cells.
Song Qin - One of the best experts on this subject based on the ideXlab platform.
-
Efficient purification protocol for bioengineering Allophycocyanin trimer with N-terminus Histag.
Saudi journal of biological sciences, 2017Co-Authors: Na Gao, Zhihong Tang, Lufei Song, Song QinAbstract:Allophycocyanin plays a key role for the photon energy transfer from the phycobilisome to reaction center chlorophylls with high efficiency in cyanobacteria. Previously, the high soluble self-assembled bioengineering Allophycocyanin trimer with N-terminus polyhistidine from Synechocystis sp. PCC 6803 had been successfully recombined and expressed in Escherichia coli strain. The standard protocol with immobilized metal-ion affinity chromatography with chelating transition metal ion (Ni2+) was used to purify the recombinant protein. Extensive optimization works were performed to obtain the desired protocol for high efficiency, low disassociation, simplicity and fitting for large-scale purification. In this study, a 33 full factorial response surface methodology was employed to optimize the varied factors such as pH of potassium phosphate (X1), NaCl concentration (X2), and imidazole concentration (X3). A maximum trimerization ratio (Y1) of approximate A650 nm/A620 nm at 1.024 was obtained at these optimum parameters. Further examinations, with absorbance spectra, fluorescence spectra and SDS-PAGE, confirmed the presence of bioengineering Allophycocyanin trimer with highly trimeric form. All these results demonstrate that optimized protocol is efficient in purification of bioengineering Allophycocyanin trimer with Histag.
-
Photocurrent generation by recombinant Allophycocyanin trimer multilayer on TiO2 electrode
Chinese Chemical Letters, 2013Co-Authors: Guoliang Zhu, Yipeng Wang, Song QinAbstract:A recombinant Allophycocyanin trimer was successfully immobilized on a rnesoporous TiO2 electrode. The formation of the immobilized surface was confirmed by multilayer adsorption of protein complexes. The key biophotovoltaic parameters were obtained, which showed that the recombinant Allophycocyanin trimer could be a candidate for photosensitizer materials. The values of short-circuit current, open-circuit voltage, fill factor, and conversion efficiency were up to 0.73 mA/cm(2), 0.52 V, 0.69, and 0.26%, respectively. (C) 2012 Bao-Sheng Ge. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
-
Biosynthesis of a stable Allophycocyanin beta subunit in metabolically engineered Escherichia coli.
Journal of bioscience and bioengineering, 2012Co-Authors: Huaxin Chen, Hanzhi Lin, Peng Jiang, Song QinAbstract:Allophycocyanin (APC) is widely used as a fluorescent tag for fluorescence detection techniques. In this study, the alpha pcB gene from a thermophilic cyanobacterium strain was cloned and ligated into an expression vector to construct a pathway for the biosynthesis of an Allophycocyanin beta subunit (holo-apcBT) in Escherichia coli. Isopropyl beta-D-1-thiogalactopyranoside induction successfully reconstituted holo-apcBT in E. coli. The recombinant holo-apcB showed spectroscopic properties similar to native APC. The stability and spectroscopic properties of this protein were then compared with another recombinant Allophycocyanin beta subunit (holo-apcBM) whose apcB gene was cloned from mesophilic cyanobacterium. At high temperatures and during the course of storage, holo-apcBT was significantly more stable than holo-apcBM. In addition, holo-apcBT had an unexpectedly higher extinction coefficient and fluorescence quantum yield than holo-apcBM, suggesting that holo-apcBT would be a promising fluorescent tag and serve as a substitute for native APC. (c) 2012, The Society for Biotechnology, Japan. All rights reserved.
-
Biosynthesis and immobilization of biofunctional Allophycocyanin.
Evidence-based complementary and alternative medicine : eCAM, 2011Co-Authors: Yingjie Chen, Huaxin Chen, Peng Jiang, Shaofang Liu, Yulin Cui, Song QinAbstract:The holo-Allophycocyanin-α subunit, which has various reported pharmacological uses, was biosynthesized with both Strep-II-tag and His-tag at the N-terminal in Escherichia coli. The streptavidin-binding ability resulting from the Strep II-tag was confirmed by Western blot. Additionally, the metal-chelating ability deriving from the His-tag not only facilitated its purification by immobilized metal-ion affinity chromatography but also promoted its immobilization on Zn (II)-decorated silica-coated magnetic nanoparticles. The holo-Allophycocyanin-α subunit with streptavidin-binding ability was thereby immobilized on magnetic nanoparticles. Magnetic nanoparticles are promising as drug delivery vehicles for targeting and locating at tumors. Thus, based on genetic engineering and nanotechnology, we provide a potential strategy to facilitate the biomodification and targeted delivery of pharmacological proteins.
-
ANTIOXIDANT PROPERTIES OF RECOMBINANT Allophycocyanin EXPRESSED IN ESCHERICHIA COLI
Journal of photochemistry and photobiology. B Biology, 2006Co-Authors: Song Qin, Lu Han, Fan Lin, Yuhong RenAbstract:Allophycocyanin (A-PC) is the main core component of phycobilisome found in blue-green algae. The apo-Allophycocyanin and its subunits were expressed in Escherichia coli and their antioxidant properties were evaluated using deoxyribose assay. The result showed that both recombinant Allophycocyanin fused with maltose binding protein (MBP) tag and 6 x His-tag and their alpha or beta subunits can scavenge hydroxyl radicals successfully, and the separated g or beta subunits had a higher inhibition effect on hydroxyl radicals than that when they combined together. The scavenging effects increased with the increasing concentration. These results clearly suggested that apo-Allophycocyanin is involved in the antioxidant and radical scavenging activity of phycocyanin, and the antioxidant activity may be partially responsible to the anti-tumor effect of the recombinant Allophycocyanin. (c) 2006 Elsevier B.V. All rights reserved.
James Barber - One of the best experts on this subject based on the ideXlab platform.
-
the structure of Allophycocyanin from thermosynechococcus elongatus at 3 5 a resolution
Acta Crystallographica Section F-structural Biology and Crystallization Communications, 2007Co-Authors: James William Murray, Karim Maghlaoui, James BarberAbstract:Cyanobacteria and red algae use light-harvesting pigments bound by proteins to capture solar radiation and to channel excitation energy into their reaction centres. In most cyanobacteria, a multi-megadalton soluble structure known as the phycobilisome is a major light-harvesting system. Allophycocyanin is the main component of the phycobilisome core, forming a link between the rest of the phycobilisome and the reaction-centre core. The crystal structure of Allophycocyanin from Thermosynechococcus elongatus (TeAPC) has been determined and refined at 3.5 A resolution to a crystallographic R value of 26.0% (R free = 28.5%). The structure was solved by molecular replacement using the Allophycocyanin structure from Spirulina platensis as the search model. The asymmetric unit contains an (αβ) monomer which is expanded by symmetry to a crystallographic trimer.
-
The structure of Allophycocyanin from Thermosynechococcus elongatus at 3.5 A resolution.
Acta crystallographica. Section F Structural biology and crystallization communications, 2007Co-Authors: James William Murray, Karim Maghlaoui, James BarberAbstract:Cyanobacteria and red algae use light-harvesting pigments bound by proteins to capture solar radiation and to channel excitation energy into their reaction centres. In most cyanobacteria, a multi-megadalton soluble structure known as the phycobilisome is a major light-harvesting system. Allophycocyanin is the main component of the phycobilisome core, forming a link between the rest of the phycobilisome and the reaction-centre core. The crystal structure of Allophycocyanin from Thermosynechococcus elongatus (TeAPC) has been determined and refined at 3.5 A resolution to a crystallographic R value of 26.0% (R(free) = 28.5%). The structure was solved by molecular replacement using the Allophycocyanin structure from Spirulina platensis as the search model. The asymmetric unit contains an (alphabeta) monomer which is expanded by symmetry to a crystallographic trimer.
-
Interaction of the Allophycocyanin core complex with photosystem II.
Photochemical and Photobiological Sciences, 2003Co-Authors: James Barber, Edward P Morris, Paula C. A. Da FonsecaAbstract:Allophycocyanin core complexes were purified from the thermophilic cyanobacterium Thermosynechococcus elongatus and analysed by negative-stain electron microscopy and single-particle averaging. The purified complex was found to consist of three Allophycocyanin cylinders. The single-particle analysis of end-on views of the complex revealed a mirror axis, indicative of two-fold symmetry. This observation allowed the assignment of the Allophycocyanin base cylinders and the identification of their potential interaction sites with the thylakoid membrane and with the photosystem II reaction centre in particular. The T. elongatus Allophycocyanin core projection map, together with published information on the structure of photosystem II for the same organism, was used to construct a model for the Allophycocyanin core–photosystem II dimer supercomplex, from which docking sites between both complexes are suggested. The implications of this association for energy transfer from Allophycocyanin to photosystem II are discussed.
