以水生芦苇为材料,通过吸附试验、亲和试验和荧光光谱试验探讨了沙丘芦苇(Phragmites communis Trin)的特有内含物PAAC与水芦叶绿体吸附特性及其作用位点,并在固定化的条件下研究其与水芦叶片可溶性蛋白的相互作用特点,以阐明PAAC对叶...以水生芦苇为材料,通过吸附试验、亲和试验和荧光光谱试验探讨了沙丘芦苇(Phragmites communis Trin)的特有内含物PAAC与水芦叶绿体吸附特性及其作用位点,并在固定化的条件下研究其与水芦叶片可溶性蛋白的相互作用特点,以阐明PAAC对叶绿体的保护作用机理。结果显示:(1)水芦叶绿体对PAAC的吸附符合Freundlich吸附模型,吸附量随pH的增加而增大并于pH 7.6时达到最大值(0.86μg/μg),吸附量虽随离子强度的提高而降低,但降幅较小。(2)PAAC可与水芦可溶性蛋白结合,0.26 mol/L的NaCl溶液能够洗脱与PAAC结合的蛋白质,两者间的相互作用以盐键为主,且结合蛋白质的种类特异性不明显。(3)PAAC与水芦蛋白质之间存在着相互结合作用并可能存在变构效应,它对蛋白质的荧光猝灭作用是生成PAAC-蛋白质复合物的静态猝灭,它与蛋白质的结合常数在1.0×105左右及结合位点数为1∶1。展开更多
A two-layer method based on support vector machines (SVMs) has been developed to distinguish epoxide hydrolases (EHs) from other enzymes and to classify its subfamilies using its primary protein sequences. SVM classif...A two-layer method based on support vector machines (SVMs) has been developed to distinguish epoxide hydrolases (EHs) from other enzymes and to classify its subfamilies using its primary protein sequences. SVM classifiers were built using three different feature vectors extracted from the primary sequence of EHs: the amino acid composition (AAC), the dipeptide composition (DPC), and the pseudo-amino acid composition (PAAC). Validated by 5-fold cross tests, the first layer SVM clas- sifier can differentiate EHs and non-EHs with an accuracy of 94.2% and has a Matthew’s correlation coefficient (MCC) of 0.84. Using 2-fold cross validation, PAAC-based second layer SVM can further classify EH subfamilies with an overall accuracy of 90.7% and MCC of 0.87 as compared to AAC (80.0%) and DPC (84.9%). A program called EHPred has also been developed to assist readers to recognize EHs and to classify their subfamilies using primary protein sequences with greater accuracy.展开更多
文摘以水生芦苇为材料,通过吸附试验、亲和试验和荧光光谱试验探讨了沙丘芦苇(Phragmites communis Trin)的特有内含物PAAC与水芦叶绿体吸附特性及其作用位点,并在固定化的条件下研究其与水芦叶片可溶性蛋白的相互作用特点,以阐明PAAC对叶绿体的保护作用机理。结果显示:(1)水芦叶绿体对PAAC的吸附符合Freundlich吸附模型,吸附量随pH的增加而增大并于pH 7.6时达到最大值(0.86μg/μg),吸附量虽随离子强度的提高而降低,但降幅较小。(2)PAAC可与水芦可溶性蛋白结合,0.26 mol/L的NaCl溶液能够洗脱与PAAC结合的蛋白质,两者间的相互作用以盐键为主,且结合蛋白质的种类特异性不明显。(3)PAAC与水芦蛋白质之间存在着相互结合作用并可能存在变构效应,它对蛋白质的荧光猝灭作用是生成PAAC-蛋白质复合物的静态猝灭,它与蛋白质的结合常数在1.0×105左右及结合位点数为1∶1。
基金Project (No. 20542006) supported by the National Natural ScienceFoundation of China
文摘A two-layer method based on support vector machines (SVMs) has been developed to distinguish epoxide hydrolases (EHs) from other enzymes and to classify its subfamilies using its primary protein sequences. SVM classifiers were built using three different feature vectors extracted from the primary sequence of EHs: the amino acid composition (AAC), the dipeptide composition (DPC), and the pseudo-amino acid composition (PAAC). Validated by 5-fold cross tests, the first layer SVM clas- sifier can differentiate EHs and non-EHs with an accuracy of 94.2% and has a Matthew’s correlation coefficient (MCC) of 0.84. Using 2-fold cross validation, PAAC-based second layer SVM can further classify EH subfamilies with an overall accuracy of 90.7% and MCC of 0.87 as compared to AAC (80.0%) and DPC (84.9%). A program called EHPred has also been developed to assist readers to recognize EHs and to classify their subfamilies using primary protein sequences with greater accuracy.