A novel marine active polypeptide （PCF）, isolated from the gonochoric Chinese scallop, Chlamys farreri, has potential antioxidant and anti-apoptotic activity against ultraviolet irradiation. We investigated whether ...A novel marine active polypeptide （PCF）, isolated from the gonochoric Chinese scallop, Chlamys farreri, has potential antioxidant and anti-apoptotic activity against ultraviolet irradiation. We investigated whether UVB-induced HaCaT cell apoptosis occurs via the mitochondrial pathways Apaf-1/caspase-9 and Smac/XIAP/caspase-3. We then investigated the molecular mechanisms controlling the anti-apoptotic effect of PCE Pre-treatment with PCF and caspase-9 inhibitor significantly inhibited UVB-induced apoptosis in HaCaT cells based on a DNA fragmentation assay and Hoechst 33258 staining The expression of Apaf-1 and the cleavage of procaspase-9 were dose-dependently reduced by 1.42-5.96 mmol/L PCF pretreatment in UVB-irradiated HaCaT cells. This was followed by inhibition of cleavage of procaspase-3, whose activation induced cell apoptosis. Meanwhile, PCF significantly and dose-dependently enhanced the activation of ATPase. Furthermore, we demonstrated that PCF strongly inhibited the release of Smac from the mitochondria to cytosol by reducing the degradation of XIAP dose-dependently. We conclude that the protective effect of PCF against UVB irradiation in HaCaT cells may be attributed to the inhibition of the Apaf-1/caspase-9 and Smac/XIAP/caspase-3 apoptotic signaling pathways.展开更多
High-throughput quantification with label-free methods has received considerable attention in electrospray ionization(ESI)-mass spectrometry(MS),but the manner by which MS signals respond to peptide concentration rema...High-throughput quantification with label-free methods has received considerable attention in electrospray ionization(ESI)-mass spectrometry(MS),but the manner by which MS signals respond to peptide concentration remains unclear in proteomics.We developed a new mathematical formula to describe the intrinsic log-log relationship between the MS intensity response and peptide concentration in an analytical ESI process.Experimental results showed that the calibration curve is fairly fit to the log-log formula with a linear dynamic range of approximate four to five orders of magnitude.However,we found that the ionization of analytical peptides can be severely suppressed by coexisting matrix peptides,such that the calibration curve can be poorly leveled off on both ends.Our study suggests that the interferences from coexisting matrix peptides should be reduced in the ESI process to use the log-log calibration curve successfully for the high-throughput quantification.展开更多
We describe an implementation of the cluster-in-molecule （CIM） resolution of the identity （RI） approximation second-order Moller-Plesset perturbation theory （CIM-RI-MP2）, with the purpose of extending RI-MP2 cal...We describe an implementation of the cluster-in-molecule （CIM） resolution of the identity （RI） approximation second-order Moller-Plesset perturbation theory （CIM-RI-MP2）, with the purpose of extending RI-MP2 calculations to very large systems. For typical conformers of several large polypeptides, we calculated their conformational energy differences with the CIM-RI-MP2 and the generalized energy-based fragmentation MP2 （GEBF-MP2） methods, and compared these results with the density functional theory （DFT） results obtained with several popular functionals. Our calculations show that the conformational energy differences obtained with CIM-RI-MP2 and GEBF-MP2 are very close to each other. In comparison with the GEBF-MP2 and CIM-RI-MP2 relative energies, we found that the DFT functionals （CAM-B3LYP-D3, LC-ωPBE-D3, M05-2X, M06-2X and coB97XD） can give quite accurate conformational energy differences for structurally similar conformers, but provide less-accurate results for structurally very different conformers.展开更多
基金Supported by the National Natural Science Foundation of China (No 30471458)the Natural Science Foundation of Shandong Province,China (No Z2007c09)
文摘A novel marine active polypeptide （PCF）, isolated from the gonochoric Chinese scallop, Chlamys farreri, has potential antioxidant and anti-apoptotic activity against ultraviolet irradiation. We investigated whether UVB-induced HaCaT cell apoptosis occurs via the mitochondrial pathways Apaf-1/caspase-9 and Smac/XIAP/caspase-3. We then investigated the molecular mechanisms controlling the anti-apoptotic effect of PCE Pre-treatment with PCF and caspase-9 inhibitor significantly inhibited UVB-induced apoptosis in HaCaT cells based on a DNA fragmentation assay and Hoechst 33258 staining The expression of Apaf-1 and the cleavage of procaspase-9 were dose-dependently reduced by 1.42-5.96 mmol/L PCF pretreatment in UVB-irradiated HaCaT cells. This was followed by inhibition of cleavage of procaspase-3, whose activation induced cell apoptosis. Meanwhile, PCF significantly and dose-dependently enhanced the activation of ATPase. Furthermore, we demonstrated that PCF strongly inhibited the release of Smac from the mitochondria to cytosol by reducing the degradation of XIAP dose-dependently. We conclude that the protective effect of PCF against UVB irradiation in HaCaT cells may be attributed to the inhibition of the Apaf-1/caspase-9 and Smac/XIAP/caspase-3 apoptotic signaling pathways.
基金supported by the National Basic Research Program of China(2010CB912700,2013CB911201,2011CB910600)the National High Technology Research and Development Program of China(2012AA020203,2014AAQ00361)the National Natural Science Foundation of China(21227805)
文摘High-throughput quantification with label-free methods has received considerable attention in electrospray ionization(ESI)-mass spectrometry(MS),but the manner by which MS signals respond to peptide concentration remains unclear in proteomics.We developed a new mathematical formula to describe the intrinsic log-log relationship between the MS intensity response and peptide concentration in an analytical ESI process.Experimental results showed that the calibration curve is fairly fit to the log-log formula with a linear dynamic range of approximate four to five orders of magnitude.However,we found that the ionization of analytical peptides can be severely suppressed by coexisting matrix peptides,such that the calibration curve can be poorly leveled off on both ends.Our study suggests that the interferences from coexisting matrix peptides should be reduced in the ESI process to use the log-log calibration curve successfully for the high-throughput quantification.
基金supported by the National Natural Science Foundation of China(21073086,21333004)the National Basic Research Program of China(2011CB808501)
文摘We describe an implementation of the cluster-in-molecule （CIM） resolution of the identity （RI） approximation second-order Moller-Plesset perturbation theory （CIM-RI-MP2）, with the purpose of extending RI-MP2 calculations to very large systems. For typical conformers of several large polypeptides, we calculated their conformational energy differences with the CIM-RI-MP2 and the generalized energy-based fragmentation MP2 （GEBF-MP2） methods, and compared these results with the density functional theory （DFT） results obtained with several popular functionals. Our calculations show that the conformational energy differences obtained with CIM-RI-MP2 and GEBF-MP2 are very close to each other. In comparison with the GEBF-MP2 and CIM-RI-MP2 relative energies, we found that the DFT functionals （CAM-B3LYP-D3, LC-ωPBE-D3, M05-2X, M06-2X and coB97XD） can give quite accurate conformational energy differences for structurally similar conformers, but provide less-accurate results for structurally very different conformers.
