The sonocatalytic damage of bovine serum albumin （BSA） was studied in the presence of nanometer titanium dioxide （TiO2） powders by low frequency （80 kHz） ultrasound. The destruction of secondary structure and ch...The sonocatalytic damage of bovine serum albumin （BSA） was studied in the presence of nanometer titanium dioxide （TiO2） powders by low frequency （80 kHz） ultrasound. The destruction of secondary structure and change of α-helical structure of BSA were reflected by ultraviolet （UV） and circular dichroism （CD） spectroscopies.展开更多
The interaction of raltitrexed（RTX） with bovine serum albumin（BSA） was investigated by steady state/lifetime fluorescence spectroscopy and circular dichroism（CD） spectroscopy under the simulative physiological c...The interaction of raltitrexed（RTX） with bovine serum albumin（BSA） was investigated by steady state/lifetime fluorescence spectroscopy and circular dichroism（CD） spectroscopy under the simulative physiological conditions.The results of fluorescence titration reveal that RTX could strongly quench the intrinsic fluorescence of BSA via a static quenching procedure.The obtained binding constant K A of RTX with BSA was 478630 and 44259 L/mol at 298 and 310 K,respectively.According to van＇t Hoff equation,the thermodynamic parameters ΔH,ΔG and ΔS were calculated,indicating that hydrophobic forces were the predominant intermolecular forces in stabilizing the complex.The binding process was a spontaneous process,in which Gibbs free energy change was negative.According to F rster＇s non-radioactive energy transfer theory,the distance r between donor（BSA） and acceptor（RTX） was 3.82 nm,suggesting that the energy transfer from BSA to RTX occurred with high probability.Displacement experiment and the number of binding sites calculation confirmed that RTX could bind to the site-I of BSA.Furthermore,the effects of pH and some metal ions on the interaction of RTX with BSA were also investigated.The results of synchronous fluorescence and CD spectra show that the RTX-BSA binding induced conformational changes in BSA.展开更多
The optimization of the scaffolds to provide a suitable matrix and accelerate the regeneration process is vital for bone tissue engineering.However,poor mechanical and biological characteristics remain the primary cha...The optimization of the scaffolds to provide a suitable matrix and accelerate the regeneration process is vital for bone tissue engineering.However,poor mechanical and biological characteristics remain the primary challenges that must be addressed.For example,although bredigite(Br)has shown great potential for application in bone tissue engineering,it easily fails in replacement.In the present work,these challenges are addressed by reinforcing the Br matrix with nanosheets of graphene oxide(rGO)that have been reduced by bovine serum albumin(BSA)in order to enhance the mechanical properties and biological behavior.The reduction of graphene oxide by BSA improves the water stability of the nanosheets and provides an electrostatic interaction between theBSA-rGO nanosheets and theBr particles.The high thermal conductivity of theBSA-rGO nanosheets decreases the porosity of the Br by transferring heat to the core of the tablet.Furthermore,the addition of BSA-rGO nanosheets into the Br matrix enhances the adhesion of G-292 cells on the surface of the tablets.These findings suggest that the tablet consisting of BSA-rGO-reinforced Br has encouraging potential for application in bone tissue engineering.展开更多
The interaction of baicalein with bovine serum albumin（BSA） was investigated with the help of spectroscopic and molecular docking studies.The binding affinity of baicalein towards BSA was estimated to be in order of...The interaction of baicalein with bovine serum albumin（BSA） was investigated with the help of spectroscopic and molecular docking studies.The binding affinity of baicalein towards BSA was estimated to be in order of 10~5 M^（-1） from fluorescence quenching studies.Negative ΔH°（-5.66 ＋ 0.14 kJ/mol） and positive（ΔS°）（＋ 79.96 ＋ 0.65J/mol K） indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°.The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate（SDS） due to probable hydrophobic association of baicalein with SDS,resulting in a negative ΔS°（-40.65 ＋ 0.87 J/mol K）.Matrix-assisted laser desorption ionization/time of flight（MALDI-TOF） experiments indicate a 1：1 complexation between baicalein and BSA.The unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime measurements.It was observed that the presence of urea ruptured the non-covalent interaction between baicalein and BSA.The presence of metal ions（Ag~＋,Mg^（2＋）,Ni^（2＋）,Mn^（2＋）,Co^（2＋） and Zn^（2＋）） increased the binding affinity of ligand towards BSA.The changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism（CD） and Fourier transform infrared（FT-IR） spectroscopic techniques.Site selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1（subdomain MA） of BSA.展开更多
Characterizing how chemical compounds binding to serum albumin is essential in evaluating drug candidates and is the focus of this study. A surface plasmon resonance biosenser developed in this laboratory was used to ...Characterizing how chemical compounds binding to serum albumin is essential in evaluating drug candidates and is the focus of this study. A surface plasmon resonance biosenser developed in this laboratory was used to determine the binding constants of antibiotics with serum albumin. The binding constants of five antibiotics（asithromycin, spectinomycin, gentamycin, metacycline and kanamycin） with serum albumins were obtained.展开更多
The interactions of mixed porphyrin-polypyridyl Ru（Ⅱ） complexes [m（Py-3＇）TPP-Ru（phen）2Cl]^＋（1） and its derivatives [Nim（Py-3＇）TPP-Ru（phen）2Cl]＋（2） and [Cum（Py-3＇）TPP-Ru（phen）2Cl]^＋（3）（phen=...The interactions of mixed porphyrin-polypyridyl Ru（Ⅱ） complexes [m（Py-3＇）TPP-Ru（phen）2Cl]^＋（1） and its derivatives [Nim（Py-3＇）TPP-Ru（phen）2Cl]＋（2） and [Cum（Py-3＇）TPP-Ru（phen）2Cl]^＋（3）（phen=1,10-phenanthroline; m（Py-3＇）TPP=5-（3＇-pyridyl）-10,15,20-triphenylporphyrin） with bovine serum albumin（BSA） were investigated by fluorescence, UV-Vis and circular dichroism（CD） spectroscopies. The UV-Vis and CD spectral experiments indicated that the secondary structures of the protein were perturbed in the presence of the porphyrin Ru（Ⅱ） complex and the perturbation was enhanced under the irradiation with ultra-violet light. The fluorescence quenching mechanism of BSA by the three complexes was determined to be a static process, and the apparent binding constant K values for complexes 1, 2 and 3 measured by fluorescence quenching method were （3.86±0.03）×10^3 L/mol（n=0.94±0.04）, （5.69±0.04）× 103 L/mol（n=1.03±0.06）, and （6.54±0.02）× 10^3 L/mol（n=1.03±0.05）, respectively.展开更多
Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in t...Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in the presence and absence of chelating agents,can be used as the criterion to evaluate the mobilizing capability of chelating agent.The F values determined experimentally lead to a mobilizing capability order:DTPA>EDTA>EGTA>NTA>TR1EN>PEN>CYS>HIS>SAThe polyaminopolycarboxylate type chelators mobilize cadmium effectively.A linear relationship was found between 1gF and lg k'CdL (conditional stability constant of the cadmium chelate).展开更多
基金We greatly acknowledge the National Natural Science Foundation of China for financial support.
文摘The sonocatalytic damage of bovine serum albumin （BSA） was studied in the presence of nanometer titanium dioxide （TiO2） powders by low frequency （80 kHz） ultrasound. The destruction of secondary structure and change of α-helical structure of BSA were reflected by ultraviolet （UV） and circular dichroism （CD） spectroscopies.
基金Supported by the National Natural Science Foundation of China(No.30973659)
文摘The interaction of raltitrexed（RTX） with bovine serum albumin（BSA） was investigated by steady state/lifetime fluorescence spectroscopy and circular dichroism（CD） spectroscopy under the simulative physiological conditions.The results of fluorescence titration reveal that RTX could strongly quench the intrinsic fluorescence of BSA via a static quenching procedure.The obtained binding constant K A of RTX with BSA was 478630 and 44259 L/mol at 298 and 310 K,respectively.According to van＇t Hoff equation,the thermodynamic parameters ΔH,ΔG and ΔS were calculated,indicating that hydrophobic forces were the predominant intermolecular forces in stabilizing the complex.The binding process was a spontaneous process,in which Gibbs free energy change was negative.According to F rster＇s non-radioactive energy transfer theory,the distance r between donor（BSA） and acceptor（RTX） was 3.82 nm,suggesting that the energy transfer from BSA to RTX occurred with high probability.Displacement experiment and the number of binding sites calculation confirmed that RTX could bind to the site-I of BSA.Furthermore,the effects of pH and some metal ions on the interaction of RTX with BSA were also investigated.The results of synchronous fluorescence and CD spectra show that the RTX-BSA binding induced conformational changes in BSA.
基金Thiswork is financially supported by IranUniversity of Science and Technology(IUST)and Motamed Cancer Institute(ACECR).
文摘The optimization of the scaffolds to provide a suitable matrix and accelerate the regeneration process is vital for bone tissue engineering.However,poor mechanical and biological characteristics remain the primary challenges that must be addressed.For example,although bredigite(Br)has shown great potential for application in bone tissue engineering,it easily fails in replacement.In the present work,these challenges are addressed by reinforcing the Br matrix with nanosheets of graphene oxide(rGO)that have been reduced by bovine serum albumin(BSA)in order to enhance the mechanical properties and biological behavior.The reduction of graphene oxide by BSA improves the water stability of the nanosheets and provides an electrostatic interaction between theBSA-rGO nanosheets and theBr particles.The high thermal conductivity of theBSA-rGO nanosheets decreases the porosity of the Br by transferring heat to the core of the tablet.Furthermore,the addition of BSA-rGO nanosheets into the Br matrix enhances the adhesion of G-292 cells on the surface of the tablets.These findings suggest that the tablet consisting of BSA-rGO-reinforced Br has encouraging potential for application in bone tissue engineering.
基金Department of Science and Technology(DST,Project no.SR/SO/BB-54/2007),Government of India for financial support
文摘The interaction of baicalein with bovine serum albumin（BSA） was investigated with the help of spectroscopic and molecular docking studies.The binding affinity of baicalein towards BSA was estimated to be in order of 10~5 M^（-1） from fluorescence quenching studies.Negative ΔH°（-5.66 ＋ 0.14 kJ/mol） and positive（ΔS°）（＋ 79.96 ＋ 0.65J/mol K） indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°.The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate（SDS） due to probable hydrophobic association of baicalein with SDS,resulting in a negative ΔS°（-40.65 ＋ 0.87 J/mol K）.Matrix-assisted laser desorption ionization/time of flight（MALDI-TOF） experiments indicate a 1：1 complexation between baicalein and BSA.The unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime measurements.It was observed that the presence of urea ruptured the non-covalent interaction between baicalein and BSA.The presence of metal ions（Ag~＋,Mg^（2＋）,Ni^（2＋）,Mn^（2＋）,Co^（2＋） and Zn^（2＋）） increased the binding affinity of ligand towards BSA.The changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism（CD） and Fourier transform infrared（FT-IR） spectroscopic techniques.Site selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1（subdomain MA） of BSA.
文摘Characterizing how chemical compounds binding to serum albumin is essential in evaluating drug candidates and is the focus of this study. A surface plasmon resonance biosenser developed in this laboratory was used to determine the binding constants of antibiotics with serum albumin. The binding constants of five antibiotics（asithromycin, spectinomycin, gentamycin, metacycline and kanamycin） with serum albumins were obtained.
基金Supported by the National Natural Science Foundation of China(Nos.20871056, 20771044 and 20901030)the Natural Science Foundation of Guangdong Province, China(Nos.8251063201000008 and 9451063201002077)+1 种基金the Planned Item of Science and Technology of Guangdong Province, China (No.2008A030201020)the "211" Project Grant of Jinan University,China
文摘The interactions of mixed porphyrin-polypyridyl Ru（Ⅱ） complexes [m（Py-3＇）TPP-Ru（phen）2Cl]^＋（1） and its derivatives [Nim（Py-3＇）TPP-Ru（phen）2Cl]＋（2） and [Cum（Py-3＇）TPP-Ru（phen）2Cl]^＋（3）（phen=1,10-phenanthroline; m（Py-3＇）TPP=5-（3＇-pyridyl）-10,15,20-triphenylporphyrin） with bovine serum albumin（BSA） were investigated by fluorescence, UV-Vis and circular dichroism（CD） spectroscopies. The UV-Vis and CD spectral experiments indicated that the secondary structures of the protein were perturbed in the presence of the porphyrin Ru（Ⅱ） complex and the perturbation was enhanced under the irradiation with ultra-violet light. The fluorescence quenching mechanism of BSA by the three complexes was determined to be a static process, and the apparent binding constant K values for complexes 1, 2 and 3 measured by fluorescence quenching method were （3.86±0.03）×10^3 L/mol（n=0.94±0.04）, （5.69±0.04）× 103 L/mol（n=1.03±0.06）, and （6.54±0.02）× 10^3 L/mol（n=1.03±0.05）, respectively.
文摘Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in the presence and absence of chelating agents,can be used as the criterion to evaluate the mobilizing capability of chelating agent.The F values determined experimentally lead to a mobilizing capability order:DTPA>EDTA>EGTA>NTA>TR1EN>PEN>CYS>HIS>SAThe polyaminopolycarboxylate type chelators mobilize cadmium effectively.A linear relationship was found between 1gF and lg k'CdL (conditional stability constant of the cadmium chelate).
