A hydrothermal reaction of copper acetate with ammonium molybdate, 4,4-bpy (4,4-bipyridine) and 1,10-phen (1,10-phenanthroline) led to the formation of brown crystals of [Cu2(1,10-phen)2(4,4-bpy)]2 [Mo8O26]4H2O 1. Si...A hydrothermal reaction of copper acetate with ammonium molybdate, 4,4-bpy (4,4-bipyridine) and 1,10-phen (1,10-phenanthroline) led to the formation of brown crystals of [Cu2(1,10-phen)2(4,4-bpy)]2 [Mo8O26]4H2O 1. Single-crystal X-ray analysis has revealed that 1 (C68H56N12O30Cu4Mo8) crystallizes in the triclinic system, space group P with a = 11.270(3), b = 13.113(6), c = 13.906(3) ? = 103.33(4), b = 98.54(2), g = 101.29(2)? V = 1920.1(1) ?3, Mr = 2542.93, Z = 1, Dc = 2.199 g/cm3, m = 2.435 mm-1, F(000) = 1240, the final R = 0.0445, wR = 0.1082 and S = 1.021 for 5052 observed reflections with I >2s(I). It consists of copper (Ⅰ) tetramer units and -[Mo8O26]4- anions, which are further attached into a three-dimensional framework through hydrogen bonding and - stacking interactions.展开更多
A new isopropenyl benzofuran-type tetramer was isolated from the roots of ligularia stenocephala and its structure was established by spectroscopic methods.
N-acetylatedα-synuclein(αSyn)has long been established as an intrinsically disordered protein associated with a dysfunctional role in Parkinson’s disease.In recent years,a physiologically relevant,higher order conf...N-acetylatedα-synuclein(αSyn)has long been established as an intrinsically disordered protein associated with a dysfunctional role in Parkinson’s disease.In recent years,a physiologically relevant,higher order conformation has been identified as a helical tetramer that is tailored by buried hydrophobic interactions and is distinctively aggregation resistant.The canonical mechanism by which the tetramer assembles remains elusive.As novel biochemical approaches,computational methods,pioneering purification platforms,and powerful imaging techniques continue to develop,puzzling information that once sparked debate as to the veracity of the tetramer has now shed light upon this new counterpart inαSyn neurobiology.Nuclear magnetic resonance and computational studies on multimericαSyn structure have revealed that the protein folding propensity is controlled by small energy barriers that enable large scale reconfiguration.Alternatively,familial mutations ablate tetramerization and reconfigure polymorphic fibrillization.In this review,we will discuss the dynamic landscape ofαSyn quaternary structure with a focus on the tetrameric conformation.展开更多
To study the influence of ethanol molecules on the melittin tetramer folding,we investigated the dewetting transition of the melittin tetramer immersed in pure water and 8%aqueous ethanol solution(mass fraction) by th...To study the influence of ethanol molecules on the melittin tetramer folding,we investigated the dewetting transition of the melittin tetramer immersed in pure water and 8%aqueous ethanol solution(mass fraction) by the molecular dynamics simulations.We found that the marked dewetting transitions occurred inside a nanoscale channel of the melittin tetramer both in pure water and in aqueous ethanol solution.Also,ethanol molecules promoted this dewetting transition.We attributed this promoting effect to ethanol molecules which prefer to locate at the liquidvapor interface and decrease the liquid-vapor surface energy.The results provide insight into the effect of ethanol on the water dewetting phenomena.展开更多
A new resveratrol tetramer, sinicin A was isolated from the roots of Ampelopsis sinica, with four known tetramers: vitisin A, cis-vitisin B, ampelopsin H and hopeaphenol. The structure and stereochemistry of sinicin A...A new resveratrol tetramer, sinicin A was isolated from the roots of Ampelopsis sinica, with four known tetramers: vitisin A, cis-vitisin B, ampelopsin H and hopeaphenol. The structure and stereochemistry of sinicin A have been established on the basis of 1D and 2D NMR spectroscopic techniques.展开更多
Analysis of the frequency of antigen-specific cytotoxic T lymphocytes (CTLs) ex vivo is largely dependent on the use of MHC/peptide tetramers. However, the latter reagents have not been widely available, most likely b...Analysis of the frequency of antigen-specific cytotoxic T lymphocytes (CTLs) ex vivo is largely dependent on the use of MHC/peptide tetramers. However, the latter reagents have not been widely available, most likely because of their costly and time-consuming production. In this report we utilized an economic strategy to construct HLA/peptide tetramers with recombinant peptide-linked β2 microglobulin (β2m). The HLA-A2-restricted, melanoma antigen MARTI-derived pep- tide MART127-35( AAGIGILTV) was fused to the N terminus of human β2m through a 15-amino acid (aa)-long linker before being refolded with the recombinant biotinylated HLA-A2 heavy chain ectodomain. The resulted 2-component (2C) monomer was then tetramerized with phycoerythin-labeled streptavidin. The experimental result showed that the 2C HLA-A2/ MART127-35 monomer was shown to bind to the HLA class complex-specific monoclonal antibody W6/32 and the HLA-A2/ MART127-35 complex-specific single chain antibody fragment (scFv) 8.3, suggesting the correctness of its specificity. Fur- thermore, the 2C HLA-A2/MART127-35 tetramer detected a specific CD8+ T cell population in HLA-A2-restricted melanoma infiltrating lymphocytes as the conventional 3C HLA-A2/MART127-35 tetramer. The yield of 2C HLA-A2/MART127-35 monomer was 2. 5 times more than that of the conventional 3C monomer. Taken together, these data indicate that the HLA-A2/ MART127-35 tetramer can be generated conveniently through the use of MART127-35 peptide-β2 m fusion proteins, which can fa- cilitate the monitoring of HLA-A2-restricted, MART1-specific CTL responses in patients with melanoma.展开更多
基金This work was supported by the National Natural Science Foundation of China (20073048) NSF of Fujian and the Chinese Academy of Sciences
文摘A hydrothermal reaction of copper acetate with ammonium molybdate, 4,4-bpy (4,4-bipyridine) and 1,10-phen (1,10-phenanthroline) led to the formation of brown crystals of [Cu2(1,10-phen)2(4,4-bpy)]2 [Mo8O26]4H2O 1. Single-crystal X-ray analysis has revealed that 1 (C68H56N12O30Cu4Mo8) crystallizes in the triclinic system, space group P with a = 11.270(3), b = 13.113(6), c = 13.906(3) ? = 103.33(4), b = 98.54(2), g = 101.29(2)? V = 1920.1(1) ?3, Mr = 2542.93, Z = 1, Dc = 2.199 g/cm3, m = 2.435 mm-1, F(000) = 1240, the final R = 0.0445, wR = 0.1082 and S = 1.021 for 5052 observed reflections with I >2s(I). It consists of copper (Ⅰ) tetramer units and -[Mo8O26]4- anions, which are further attached into a three-dimensional framework through hydrogen bonding and - stacking interactions.
基金supoaed by the National Natural Science Foundation of China(No.29972017)
文摘A new isopropenyl benzofuran-type tetramer was isolated from the roots of ligularia stenocephala and its structure was established by spectroscopic methods.
基金supported in part by Award No.18-7(to HRL)from the Commonwealth of Virginia’s Alzheimer’s and Related Diseases Research Award Fund,administered by the Virginia Center on Aging
文摘N-acetylatedα-synuclein(αSyn)has long been established as an intrinsically disordered protein associated with a dysfunctional role in Parkinson’s disease.In recent years,a physiologically relevant,higher order conformation has been identified as a helical tetramer that is tailored by buried hydrophobic interactions and is distinctively aggregation resistant.The canonical mechanism by which the tetramer assembles remains elusive.As novel biochemical approaches,computational methods,pioneering purification platforms,and powerful imaging techniques continue to develop,puzzling information that once sparked debate as to the veracity of the tetramer has now shed light upon this new counterpart inαSyn neurobiology.Nuclear magnetic resonance and computational studies on multimericαSyn structure have revealed that the protein folding propensity is controlled by small energy barriers that enable large scale reconfiguration.Alternatively,familial mutations ablate tetramerization and reconfigure polymorphic fibrillization.In this review,we will discuss the dynamic landscape ofαSyn quaternary structure with a focus on the tetrameric conformation.
基金supported by the National Science Foundation of China(No.10975175,90923002,21073222)Chinese Academy of Sciences(No.KJCX2-EW-N03)
文摘To study the influence of ethanol molecules on the melittin tetramer folding,we investigated the dewetting transition of the melittin tetramer immersed in pure water and 8%aqueous ethanol solution(mass fraction) by the molecular dynamics simulations.We found that the marked dewetting transitions occurred inside a nanoscale channel of the melittin tetramer both in pure water and in aqueous ethanol solution.Also,ethanol molecules promoted this dewetting transition.We attributed this promoting effect to ethanol molecules which prefer to locate at the liquidvapor interface and decrease the liquid-vapor surface energy.The results provide insight into the effect of ethanol on the water dewetting phenomena.
基金This research program was supported by the National Natural Science Foundation of China (No. 30070+2 种基金889). The authors thank the Department of Instrumental Analysis Institute of Materia Medica Chinese Academy of Medical Sciences & Peking Union Col
文摘A new resveratrol tetramer, sinicin A was isolated from the roots of Ampelopsis sinica, with four known tetramers: vitisin A, cis-vitisin B, ampelopsin H and hopeaphenol. The structure and stereochemistry of sinicin A have been established on the basis of 1D and 2D NMR spectroscopic techniques.
文摘Analysis of the frequency of antigen-specific cytotoxic T lymphocytes (CTLs) ex vivo is largely dependent on the use of MHC/peptide tetramers. However, the latter reagents have not been widely available, most likely because of their costly and time-consuming production. In this report we utilized an economic strategy to construct HLA/peptide tetramers with recombinant peptide-linked β2 microglobulin (β2m). The HLA-A2-restricted, melanoma antigen MARTI-derived pep- tide MART127-35( AAGIGILTV) was fused to the N terminus of human β2m through a 15-amino acid (aa)-long linker before being refolded with the recombinant biotinylated HLA-A2 heavy chain ectodomain. The resulted 2-component (2C) monomer was then tetramerized with phycoerythin-labeled streptavidin. The experimental result showed that the 2C HLA-A2/ MART127-35 monomer was shown to bind to the HLA class complex-specific monoclonal antibody W6/32 and the HLA-A2/ MART127-35 complex-specific single chain antibody fragment (scFv) 8.3, suggesting the correctness of its specificity. Fur- thermore, the 2C HLA-A2/MART127-35 tetramer detected a specific CD8+ T cell population in HLA-A2-restricted melanoma infiltrating lymphocytes as the conventional 3C HLA-A2/MART127-35 tetramer. The yield of 2C HLA-A2/MART127-35 monomer was 2. 5 times more than that of the conventional 3C monomer. Taken together, these data indicate that the HLA-A2/ MART127-35 tetramer can be generated conveniently through the use of MART127-35 peptide-β2 m fusion proteins, which can fa- cilitate the monitoring of HLA-A2-restricted, MART1-specific CTL responses in patients with melanoma.
