Egg water was used to induce acrosome reaction in mature sperm of Fenneropenaeus chinensis .Transmission electron microscope and SDS PAGE were used to study the ultrastructure and protein changes of the sperm in ...Egg water was used to induce acrosome reaction in mature sperm of Fenneropenaeus chinensis .Transmission electron microscope and SDS PAGE were used to study the ultrastructure and protein changes of the sperm in F.chinensis ,which has undergone acrosome reaction.The results demonstrated that the sperms from female thelycum could be induced acrosome reaction in vitro by egg water,which was a kind of egg jelly released from oocyte into seawater during oocyte activation.More than fifty percent of sperm finished acrosome reaction during the first 30 min, in vitro .The whole event consists of the retraction of the spike and acrosome exocytosis.Spike was retracted and fused to acrosome cap followed by the release of acrosome granules.When the original egg water was diluted 5 and 10 times,The diluted egg water also have the ability to induce sperm acrosome reaction,but the acrosome reaction rate is much lower than that of the original egg water in the same time.Capillary zone electrophoresis was used to detect the biochemical components of egg water.Egg water was composed of two different components,which were also demonstrated by SDS PAGE.The molecular weights of the two kinds of egg jellies are both about 200kDa.Gelatin substrate SDS PAGE results did not show any hydrolytic enzyme activity in egg water.After acrosome reaction,many sorts of proteins in sperm are degraded.When the reacted sperms were examined with gelatin substrate SDS PAGE,there were six major peptide bands with hydrolytic enzyme activity were detected.Their molecular weights are 200kDa,130 kDa,66 kDa,53 kDa,48 kDa and 41 kDa respectively.These hydrolases cannot be detected in the sperms before acrosome reaction.The acrosome reaction of Chinese shrimp, F.chinensis is much different to that of the sperm in the shrimp, Sicyonia ingentis ,which the acrosome reaction was clearly studied.There is not filament formation during the acrosome reaction in Chinese shrimp.The time of exocytosis in the sperm of Chinese shrimp is also much longer than that of the sperm of Sicyonia ingentis .展开更多
To understand how the stabilities of key nuclei fragments affect protein folding dynamics, we simulate by molecular dynamics （MD） simulation in aqueous solution four fragments cut out of a protein G, including one a...To understand how the stabilities of key nuclei fragments affect protein folding dynamics, we simulate by molecular dynamics （MD） simulation in aqueous solution four fragments cut out of a protein G, including one a-helix （seqB： KVFKQYAN）, two -turns （seqA： LNGKTLKG and seqC： YDDATKTF）, and one -strand （seqD： DGEWTYDD）. The Markov State Model clustering method combined with the coarse-grained conformation letters method are employed to analyze the data sampled from 2-#s equilibrium MD simulation trajectories. We find that seqA and seqB have more stable structures than their native structures which become metastable when cut out of the protein structure. As expected, seqD alone is flexible and does not have a stable structure. Throughout our simulations, the native structure of seqC is stable but cannot be reached if starting from a structure other than the native one, implying a funnel-shape free energy landscape of seqC in aqueous solution. All the above results suggest that different nuclei have different formation dynamics during protein folding, which may have a major contribution to the hierarchy of protein folding dynamics.展开更多
The selenium derivatization of nucleic acids and nucleic acid-protein complexes has provided a powerful tool to solve phase problem in X-ray crystallography. Selenium atoms in the nucleotides can serve as fine scatter...The selenium derivatization of nucleic acids and nucleic acid-protein complexes has provided a powerful tool to solve phase problem in X-ray crystallography. Selenium atoms in the nucleotides can serve as fine scattering centers in crystal diffraction. Towards the synthesis of multiple selenium atom-containing nucleotides, which offers strong phasing power to facilitate crys- tal structure determination, we report here the synthesis of the thymidine analogue containing two Se atoms in one nucleobase. The novel Se-containing nucleoside and oligonucleotide DNAs were synthesized and found with the red-shifted UV spectrum and yellow color. Their unique properties are useful in phase determination, nucleic acid-based detection as well as spectro- scopic studies of nucleic acids and nucleic acid-protein complexes.展开更多
文摘Egg water was used to induce acrosome reaction in mature sperm of Fenneropenaeus chinensis .Transmission electron microscope and SDS PAGE were used to study the ultrastructure and protein changes of the sperm in F.chinensis ,which has undergone acrosome reaction.The results demonstrated that the sperms from female thelycum could be induced acrosome reaction in vitro by egg water,which was a kind of egg jelly released from oocyte into seawater during oocyte activation.More than fifty percent of sperm finished acrosome reaction during the first 30 min, in vitro .The whole event consists of the retraction of the spike and acrosome exocytosis.Spike was retracted and fused to acrosome cap followed by the release of acrosome granules.When the original egg water was diluted 5 and 10 times,The diluted egg water also have the ability to induce sperm acrosome reaction,but the acrosome reaction rate is much lower than that of the original egg water in the same time.Capillary zone electrophoresis was used to detect the biochemical components of egg water.Egg water was composed of two different components,which were also demonstrated by SDS PAGE.The molecular weights of the two kinds of egg jellies are both about 200kDa.Gelatin substrate SDS PAGE results did not show any hydrolytic enzyme activity in egg water.After acrosome reaction,many sorts of proteins in sperm are degraded.When the reacted sperms were examined with gelatin substrate SDS PAGE,there were six major peptide bands with hydrolytic enzyme activity were detected.Their molecular weights are 200kDa,130 kDa,66 kDa,53 kDa,48 kDa and 41 kDa respectively.These hydrolases cannot be detected in the sperms before acrosome reaction.The acrosome reaction of Chinese shrimp, F.chinensis is much different to that of the sperm in the shrimp, Sicyonia ingentis ,which the acrosome reaction was clearly studied.There is not filament formation during the acrosome reaction in Chinese shrimp.The time of exocytosis in the sperm of Chinese shrimp is also much longer than that of the sperm of Sicyonia ingentis .
基金Supported by the National Basic Research Program of China under Grant No.2013CB932804the National Natural Science Foundation of China under Grant No.11421063the CAS Biophysics Interdisciplinary Innovation Team Project
文摘To understand how the stabilities of key nuclei fragments affect protein folding dynamics, we simulate by molecular dynamics （MD） simulation in aqueous solution four fragments cut out of a protein G, including one a-helix （seqB： KVFKQYAN）, two -turns （seqA： LNGKTLKG and seqC： YDDATKTF）, and one -strand （seqD： DGEWTYDD）. The Markov State Model clustering method combined with the coarse-grained conformation letters method are employed to analyze the data sampled from 2-#s equilibrium MD simulation trajectories. We find that seqA and seqB have more stable structures than their native structures which become metastable when cut out of the protein structure. As expected, seqD alone is flexible and does not have a stable structure. Throughout our simulations, the native structure of seqC is stable but cannot be reached if starting from a structure other than the native one, implying a funnel-shape free energy landscape of seqC in aqueous solution. All the above results suggest that different nuclei have different formation dynamics during protein folding, which may have a major contribution to the hierarchy of protein folding dynamics.
文摘The selenium derivatization of nucleic acids and nucleic acid-protein complexes has provided a powerful tool to solve phase problem in X-ray crystallography. Selenium atoms in the nucleotides can serve as fine scattering centers in crystal diffraction. Towards the synthesis of multiple selenium atom-containing nucleotides, which offers strong phasing power to facilitate crys- tal structure determination, we report here the synthesis of the thymidine analogue containing two Se atoms in one nucleobase. The novel Se-containing nucleoside and oligonucleotide DNAs were synthesized and found with the red-shifted UV spectrum and yellow color. Their unique properties are useful in phase determination, nucleic acid-based detection as well as spectro- scopic studies of nucleic acids and nucleic acid-protein complexes.
