The cytochrome P450 mutant CYP2C9.13（L90P） shows a greatly impaired catalytic activity compared with the wild-type. We constructed the mutants by substitution at residue 90 of CYP2C9, expressed in COS-7 cells, assay...The cytochrome P450 mutant CYP2C9.13（L90P） shows a greatly impaired catalytic activity compared with the wild-type. We constructed the mutants by substitution at residue 90 of CYP2C9, expressed in COS-7 cells, assayed their thermal stability and catalysis activity and analyzed the mutants via molecular dynamic（MD） simulation and flexible docking. Mutant L90E exhibits a significantly lower catalytic activity than the wild-type for the hydroxylation of diclofenac, lornoxicam and luciferin and its molecular dynamics simulation results indicate that the size of the entrance of substrate access was reduced significantly. An increase or minor decrease of catalytic activity was observed for mutants L90Q, L90W, L90R, L90I and L90G, and the sizes of the entrances of substrate access and the active site cavities had a little change in those mutants. The thermal stability and the potential energy of the MD simulation of these mutants showed a similar tendency as the catalysis assays did. Flexible docking results show the fluctuation of interaction energy is due to the change of electrostatic potential distribution. All the above facts show that the changes in the catalysis activity of the mutants caused by the substitution at residue 90 are due to the changes in the size of entrance, the shape and size of active site cavity, electrostatic potential distribution and thermal stability. The residue 90 of CYP2C9 has an important effect on the enzyme catalytic activity.展开更多
A study of the genetic structure of an ancient human excavated from the Yikeshu site of Yuanshangdu ancient city in Inner Mongolia and the relationships between the ancient population and the extant populations was ca...A study of the genetic structure of an ancient human excavated from the Yikeshu site of Yuanshangdu ancient city in Inner Mongolia and the relationships between the ancient population and the extant populations was carried out. Sequences of the control region and coding region of mtDNA from the ancient human were analyzed by using direct sequencing and restriction-fragment length polymorphism （RFLP） methods, Phylogenetic analysis and multidimensional scaling analysis were also performed on the mtDNA data of the ancient population and 12 extant populations. These results show that the ancient individuals of Yikeshu site can be assigned to D, G, B and Z haplogroups that are prevalent in Duars and Mongolians from Inner Mongolia. The ancient population is also closer to Duar and Mongolian populations in genetic distance than other compared populations. This study reveals that the ancient population from Yikeshu site in the Yuan Dynasty shares a common ancestor with Mongolic-speaking Daur and Mongolian tribes.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.30472062 and 20673044)
文摘The cytochrome P450 mutant CYP2C9.13（L90P） shows a greatly impaired catalytic activity compared with the wild-type. We constructed the mutants by substitution at residue 90 of CYP2C9, expressed in COS-7 cells, assayed their thermal stability and catalysis activity and analyzed the mutants via molecular dynamic（MD） simulation and flexible docking. Mutant L90E exhibits a significantly lower catalytic activity than the wild-type for the hydroxylation of diclofenac, lornoxicam and luciferin and its molecular dynamics simulation results indicate that the size of the entrance of substrate access was reduced significantly. An increase or minor decrease of catalytic activity was observed for mutants L90Q, L90W, L90R, L90I and L90G, and the sizes of the entrances of substrate access and the active site cavities had a little change in those mutants. The thermal stability and the potential energy of the MD simulation of these mutants showed a similar tendency as the catalysis assays did. Flexible docking results show the fluctuation of interaction energy is due to the change of electrostatic potential distribution. All the above facts show that the changes in the catalysis activity of the mutants caused by the substitution at residue 90 are due to the changes in the size of entrance, the shape and size of active site cavity, electrostatic potential distribution and thermal stability. The residue 90 of CYP2C9 has an important effect on the enzyme catalytic activity.
文摘A study of the genetic structure of an ancient human excavated from the Yikeshu site of Yuanshangdu ancient city in Inner Mongolia and the relationships between the ancient population and the extant populations was carried out. Sequences of the control region and coding region of mtDNA from the ancient human were analyzed by using direct sequencing and restriction-fragment length polymorphism （RFLP） methods, Phylogenetic analysis and multidimensional scaling analysis were also performed on the mtDNA data of the ancient population and 12 extant populations. These results show that the ancient individuals of Yikeshu site can be assigned to D, G, B and Z haplogroups that are prevalent in Duars and Mongolians from Inner Mongolia. The ancient population is also closer to Duar and Mongolian populations in genetic distance than other compared populations. This study reveals that the ancient population from Yikeshu site in the Yuan Dynasty shares a common ancestor with Mongolic-speaking Daur and Mongolian tribes.
