采用量子力学与分子力学组合的ONIOM方法,研究了赖氨酸限域在水与MOR分子筛复合环境下的手性转变.结构分析表明:2个水分子比1个水分子助氢迁移反应的过渡态分子氢键键角显著增大。反应通道研究发现:标题反应有a、b和c三个通道,是赖氨酸...采用量子力学与分子力学组合的ONIOM方法,研究了赖氨酸限域在水与MOR分子筛复合环境下的手性转变.结构分析表明:2个水分子比1个水分子助氢迁移反应的过渡态分子氢键键角显著增大。反应通道研究发现:标题反应有a、b和c三个通道,是赖氨酸在MOR分子筛限域环境下,水助质子以氨基、羰基和羟基为桥从手性碳的一侧迁移到另一侧,实现手性转变。势能面计算表明,a是主反应通道,质子从手性碳向氨基的迁移是决速步骤,在2个水分子助决速步时,吉布斯自由能垒被降到最低值101.9 k J/mol,与裸反应、限域在MOR分子筛和限域在水环境的此通道决速步能垒252.6、229.7和123.9 k J/mol相比较,均有明显降低。结果表明:水与MOR分子筛复合环境对赖氨酸手性转变具有较好的共催化作用,左旋赖氨酸在生命体内可以缓慢地旋光异构。展开更多
Three breeds of sows were observed to investigate the relationship between Single Nucleotide Polymorphisms（SNPs） in Mu Opioid Receptor（MOR）and stereotypic behaviour,such as,sham-chewing,bar biting and standing sti...Three breeds of sows were observed to investigate the relationship between Single Nucleotide Polymorphisms（SNPs） in Mu Opioid Receptor（MOR）and stereotypic behaviour,such as,sham-chewing,bar biting and standing still in order to better understand the mechanism of stereotypic development of the animals in restrained conditions.MOR exon 2 partial sequences were amplified to analyze single nucleotide polymorphisms by PCR-SSCP.One SNP,a silence mutant was found.A significant difference （P〈0.01）was found in the frequency of genotypes in these 3 breeds where only the BB genotype,which was identical to that published in GenBank,was found in the Duroc breed,while no AA genotype was found in Landrace,3 genotypes AA,BB and AB were found in Yorkshire.The result also indicated that the individuals with AA and AB genotypes tended to be more active in sham-chewing than those with the BB genotype（P〈0.05）.The overall results of this study suggested that sham-chewing of sows may be subjected to both genetic control and environmental conditions,but activity level was more likely to be affected by their environment.We can putatively draw the conclusion that MOR gene has effect on the sham-chewing behavioral traits of sow.展开更多
文摘采用量子力学与分子力学组合的ONIOM方法,研究了赖氨酸限域在水与MOR分子筛复合环境下的手性转变.结构分析表明:2个水分子比1个水分子助氢迁移反应的过渡态分子氢键键角显著增大。反应通道研究发现:标题反应有a、b和c三个通道,是赖氨酸在MOR分子筛限域环境下,水助质子以氨基、羰基和羟基为桥从手性碳的一侧迁移到另一侧,实现手性转变。势能面计算表明,a是主反应通道,质子从手性碳向氨基的迁移是决速步骤,在2个水分子助决速步时,吉布斯自由能垒被降到最低值101.9 k J/mol,与裸反应、限域在MOR分子筛和限域在水环境的此通道决速步能垒252.6、229.7和123.9 k J/mol相比较,均有明显降低。结果表明:水与MOR分子筛复合环境对赖氨酸手性转变具有较好的共催化作用,左旋赖氨酸在生命体内可以缓慢地旋光异构。
基金Supported by National Natural Sciences Foundation of China(39970533)
文摘Three breeds of sows were observed to investigate the relationship between Single Nucleotide Polymorphisms（SNPs） in Mu Opioid Receptor（MOR）and stereotypic behaviour,such as,sham-chewing,bar biting and standing still in order to better understand the mechanism of stereotypic development of the animals in restrained conditions.MOR exon 2 partial sequences were amplified to analyze single nucleotide polymorphisms by PCR-SSCP.One SNP,a silence mutant was found.A significant difference （P〈0.01）was found in the frequency of genotypes in these 3 breeds where only the BB genotype,which was identical to that published in GenBank,was found in the Duroc breed,while no AA genotype was found in Landrace,3 genotypes AA,BB and AB were found in Yorkshire.The result also indicated that the individuals with AA and AB genotypes tended to be more active in sham-chewing than those with the BB genotype（P〈0.05）.The overall results of this study suggested that sham-chewing of sows may be subjected to both genetic control and environmental conditions,but activity level was more likely to be affected by their environment.We can putatively draw the conclusion that MOR gene has effect on the sham-chewing behavioral traits of sow.
