AIM: To further analyze the interaction of tupaia CD81 with hepatitis C virus (HCV) envelope protein E2. METHODS: A tupaia CD81 large extracellular loop (CD81 LEL), which binds to HCV E2 protein, was cloned and expres...AIM: To further analyze the interaction of tupaia CD81 with hepatitis C virus (HCV) envelope protein E2. METHODS: A tupaia CD81 large extracellular loop (CD81 LEL), which binds to HCV E2 protein, was cloned and expressed as a GST-fusion protein, and interaction of HCV E2 protein with a tupaia CD81 LEL was evaluated by enzyme-linked immunosorbent assay (EIA). RESULTS: Although tupaia and human CD81 LEL differed in 6 amino acid changes, tupaia CD81 LEL was strongly recognized by anti-CD81 antibodies against human CD81 LEL conformation-dependent epitopes. Investigating LEL CD81-E2 interactions by EIA, we demonstrated that binding of tupaia CD81 LEL GST fusion protein to recombinant HCV E2 protein was markedly reduced compared to binding of human CD81 LEL GST fusion protein to recombinant HCV E2 protein. CONCLUSION: These data suggest that the structural differences in-between the tupaia and human CD81 may alter the interaction of the large extracellular loop with HCV envelope glycoprotein E2. These findings may be important for the understanding of the mechanisms of binding and entry of HCV to PTHs.展开更多
The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its ...The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its existence. Metal ions in foodstuff are in different chemical forms, as inorganic salts or organic molecules or complexes with other compounds such as proteins, amino acids, enzymes and some vitamins, among others, that play an important role in human health. Entomophagy, insect consumption by several ethnic groups in Mexico as cultural tradition since prehispanic era represent an option for population to obtain the minerals needed by the body to keep a good health. Escamoles ant eggs of the Liometopumapiculatum M genus, much appreciated either at rural communities as well as in urban cities, contain minerals with a favorable effect in human health. The aim of this study was to investigate the mineral composition of Escamoles and the benefits which can provide to the human body. Sampling was at an arid region of the Hidalgo state on April 2012. Minerals in dry basis, determined by atomic absorption spectrophotometry, with the exception of phosphorus content, obtained from a triple acid digested extract and determined colorimetrically. Data of mineral analysis in dry basis of Escamoles were： total minerals 5.92%; Na 0.079%; K 0.075%; Ca 0.097%; P 0.701%; Fe 0.021%; Zn 0.035% Cu 0.009%; Mg 0.998%; Mn 0.002%. Minerals quantify are not equal to total ash contained because not all of them were assess determined. Elements concentration depends not only on the total mineral composition of foodstuff the inorganic or organic form or interaction among metal ions, but also on their availability and avail of them. Minerals in Escamoles ant eggs have a considerable influence in the condition of human health.展开更多
The native protein structures in buffer solution are maintained by the electrostatic force as well as the hydrophobic force, salt ions play an important role in maintaining the protein native structures, and their eff...The native protein structures in buffer solution are maintained by the electrostatic force as well as the hydrophobic force, salt ions play an important role in maintaining the protein native structures, and their effect on the protein stability has attracted tremendous interests. Infrared spectroscopy has been generally used in molecular structure analysis due to its fingerprint resolution for different species including macromolecules as proteins. However spectral intensities have received much less attention than the vibrational frequencies. Here we report that the spectral intensities of protein amide I band, the finger prints for the protein secondary structures, are very sensitive to the local electric field known as Onsager reaction field caused by salt ions. IR absorbance thermal titrations have been conducted for a series of samples including simple water soluble amino acids, water soluble monomeric protein cytochrome c and dimeric protein DsbC and its single-site mutant G49R. We found that at lower temperature range （10-20℃）, there exists a thermal activated salting-in process, where the IR intensity increases with a rise in the temperature, corresponding to the ions binding of the hydrophobic surface of protein. This process is absent for the amino acids. When further raising the temperature, the IR intensity decreases, this is interpreted as the thermal activated breaking of the ion-protein surface binding. Applying Van＇t Hoff plot to the thermal titration curves, the thermodynamic parameters such as AH and AS for salting-in and ion unbinding processes can be derived for various protein secondary structural components, revealing quantitatively the extent of hydrophobic interaction as well as the strength of the ion-protein binding.展开更多
Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT), and protein precipitation ca...Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT), and protein precipitation capacity (PPC) in young, mature and senescent branchlets of Casuarina equisetifolia were studied at Chishan Forestry Center of Dongshan County, Fujian Province, China. In addition, nitrogen contents of branchlets at the different developmental stages were also determined. The contents of TP and ECT, and PPC in young branchlets were significantly higher than those in mature and senescent branchlets through the season. However, PBCT contents were significantly higher in senescent branchlets than those in young and mature branchlets; FBCT fluctuated with season. Young branchlets had the highest N content, which decreased during branch maturity and senescence. The highest contents of TP and the lowest contents of TCT and N in young and mature branchlets were observed in summer. There was a significant negative correlation between TP and N contents. In contrast, TCT contents were positively correlated to N contents. Nutrient resorption during senescence and high TCT:N ratios in senescent branchlets are the important nutrient conservation strategies for C. equisetifolia.展开更多
The rates of protein folding with photon absorption or emission and the cross section of photon-protein inelastic scattering are calculated from quantum folding theory by use of a field-theoretical method.All protein ...The rates of protein folding with photon absorption or emission and the cross section of photon-protein inelastic scattering are calculated from quantum folding theory by use of a field-theoretical method.All protein photo-folding processes are compared with common protein folding without the interaction of photons(non-radiative folding).It is demonstrated that there exists a common factor(thermo-averaged overlap integral of the vibration wave function,TAOI) for protein folding and protein photo-folding.Based on this finding it is predicted that(i) the stimulated photo-folding rates and the photon-protein resonance Raman scattering sections show the same temperature dependence as protein folding;(ii) the spectral line of the electronic transition is broadened to a band that includes an abundant vibration spectrum without and with conformational transitions,and the width of each vibration spectral line is largely reduced.The particular form of the folding rate-temperature relation and the abundant spectral structure imply the existence of quantum tunneling between protein conformations in folding and photo-folding that demonstrates the quantum nature of the motion of the conformational-electronic system.展开更多
基金Supported by Grants from Health Department of Hubei Province (JX2B09)NSFC (30771911)National 973 Key Program (2009CB522502), and Tongji Hospital
文摘AIM: To further analyze the interaction of tupaia CD81 with hepatitis C virus (HCV) envelope protein E2. METHODS: A tupaia CD81 large extracellular loop (CD81 LEL), which binds to HCV E2 protein, was cloned and expressed as a GST-fusion protein, and interaction of HCV E2 protein with a tupaia CD81 LEL was evaluated by enzyme-linked immunosorbent assay (EIA). RESULTS: Although tupaia and human CD81 LEL differed in 6 amino acid changes, tupaia CD81 LEL was strongly recognized by anti-CD81 antibodies against human CD81 LEL conformation-dependent epitopes. Investigating LEL CD81-E2 interactions by EIA, we demonstrated that binding of tupaia CD81 LEL GST fusion protein to recombinant HCV E2 protein was markedly reduced compared to binding of human CD81 LEL GST fusion protein to recombinant HCV E2 protein. CONCLUSION: These data suggest that the structural differences in-between the tupaia and human CD81 may alter the interaction of the large extracellular loop with HCV envelope glycoprotein E2. These findings may be important for the understanding of the mechanisms of binding and entry of HCV to PTHs.
文摘The earth crust is believed to be made of a mass of minerals and is matched by their importance in human life. The human body, depend like other leaving organisms, on several minerals as essential constituents of its existence. Metal ions in foodstuff are in different chemical forms, as inorganic salts or organic molecules or complexes with other compounds such as proteins, amino acids, enzymes and some vitamins, among others, that play an important role in human health. Entomophagy, insect consumption by several ethnic groups in Mexico as cultural tradition since prehispanic era represent an option for population to obtain the minerals needed by the body to keep a good health. Escamoles ant eggs of the Liometopumapiculatum M genus, much appreciated either at rural communities as well as in urban cities, contain minerals with a favorable effect in human health. The aim of this study was to investigate the mineral composition of Escamoles and the benefits which can provide to the human body. Sampling was at an arid region of the Hidalgo state on April 2012. Minerals in dry basis, determined by atomic absorption spectrophotometry, with the exception of phosphorus content, obtained from a triple acid digested extract and determined colorimetrically. Data of mineral analysis in dry basis of Escamoles were： total minerals 5.92%; Na 0.079%; K 0.075%; Ca 0.097%; P 0.701%; Fe 0.021%; Zn 0.035% Cu 0.009%; Mg 0.998%; Mn 0.002%. Minerals quantify are not equal to total ash contained because not all of them were assess determined. Elements concentration depends not only on the total mineral composition of foodstuff the inorganic or organic form or interaction among metal ions, but also on their availability and avail of them. Minerals in Escamoles ant eggs have a considerable influence in the condition of human health.
基金This work was supported by the National Natural Science Foundation of China （No.20373088）, the Program for Innovation Group （No.60321002）, the Innovative Project of Chinese Academy of Sciences （No.KJCX2-SW-w29）, and the National Key Project for Basic Research No.2006CB910302）. We thank Prof. Chih-chen Wang and Dr. Hui-min Ke in the Institute of Biophysics, Chinese Academy of Science, for the preparation of samples DsbC and G49R. We also thank Prof. Xiang-gang Qiu in the Institute of physics, Chinese Academy of Sciences, for help in FTIR measurement.
文摘The native protein structures in buffer solution are maintained by the electrostatic force as well as the hydrophobic force, salt ions play an important role in maintaining the protein native structures, and their effect on the protein stability has attracted tremendous interests. Infrared spectroscopy has been generally used in molecular structure analysis due to its fingerprint resolution for different species including macromolecules as proteins. However spectral intensities have received much less attention than the vibrational frequencies. Here we report that the spectral intensities of protein amide I band, the finger prints for the protein secondary structures, are very sensitive to the local electric field known as Onsager reaction field caused by salt ions. IR absorbance thermal titrations have been conducted for a series of samples including simple water soluble amino acids, water soluble monomeric protein cytochrome c and dimeric protein DsbC and its single-site mutant G49R. We found that at lower temperature range （10-20℃）, there exists a thermal activated salting-in process, where the IR intensity increases with a rise in the temperature, corresponding to the ions binding of the hydrophobic surface of protein. This process is absent for the amino acids. When further raising the temperature, the IR intensity decreases, this is interpreted as the thermal activated breaking of the ion-protein surface binding. Applying Van＇t Hoff plot to the thermal titration curves, the thermodynamic parameters such as AH and AS for salting-in and ion unbinding processes can be derived for various protein secondary structural components, revealing quantitatively the extent of hydrophobic interaction as well as the strength of the ion-protein binding.
基金Project supported by the National Eleventh Five-year Key Project(No.2006BAD03A14-01)Fujian Provincial Major Special Program of Science and Technology(No.2006NZ0001-2)+1 种基金the Program for New Century Excellent Talents in University(No.NCET-07-0725)the Program for Innovative Research Team in Science and Technology in Fujian Province University,China
文摘Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT), and protein precipitation capacity (PPC) in young, mature and senescent branchlets of Casuarina equisetifolia were studied at Chishan Forestry Center of Dongshan County, Fujian Province, China. In addition, nitrogen contents of branchlets at the different developmental stages were also determined. The contents of TP and ECT, and PPC in young branchlets were significantly higher than those in mature and senescent branchlets through the season. However, PBCT contents were significantly higher in senescent branchlets than those in young and mature branchlets; FBCT fluctuated with season. Young branchlets had the highest N content, which decreased during branch maturity and senescence. The highest contents of TP and the lowest contents of TCT and N in young and mature branchlets were observed in summer. There was a significant negative correlation between TP and N contents. In contrast, TCT contents were positively correlated to N contents. Nutrient resorption during senescence and high TCT:N ratios in senescent branchlets are the important nutrient conservation strategies for C. equisetifolia.
基金supported by the National Natural Science Foundation of China (Grant Nos. 202015 and 205015)
文摘The rates of protein folding with photon absorption or emission and the cross section of photon-protein inelastic scattering are calculated from quantum folding theory by use of a field-theoretical method.All protein photo-folding processes are compared with common protein folding without the interaction of photons(non-radiative folding).It is demonstrated that there exists a common factor(thermo-averaged overlap integral of the vibration wave function,TAOI) for protein folding and protein photo-folding.Based on this finding it is predicted that(i) the stimulated photo-folding rates and the photon-protein resonance Raman scattering sections show the same temperature dependence as protein folding;(ii) the spectral line of the electronic transition is broadened to a band that includes an abundant vibration spectrum without and with conformational transitions,and the width of each vibration spectral line is largely reduced.The particular form of the folding rate-temperature relation and the abundant spectral structure imply the existence of quantum tunneling between protein conformations in folding and photo-folding that demonstrates the quantum nature of the motion of the conformational-electronic system.
