Prion diseases are a class of fatal neurodegenerative diseases caused by misfolded prion proteins.The main reason is that pathogenic prion protein has a strong tendency to aggregate,which easily induces the damage to ...Prion diseases are a class of fatal neurodegenerative diseases caused by misfolded prion proteins.The main reason is that pathogenic prion protein has a strong tendency to aggregate,which easily induces the damage to the central nervous system.Point mutations in the human prion protein gene can cause prion diseases such as Creutzfeldt-Jakob and Gerstmann's syndrome.To understand the mechanism of mutation-induced prion protein aggregation,the mutants in an aqueous solution are studied by molecular dynamics simulations,including the wild type,V180I,H187R and a double point mutation which is associated with CJD and GSS.After running simulations for 500 ns,the results show that these three mutations have different effects on the kinetic properties of PrP.The high fluctuations around the N-terminal residues of helix 2 in the V180I variant lead to a decrease in hydrogen bonding on helix 2,while an increase in the number of hydrogen bonds between the folded regions promotes the generation ofβ-sheet.Meanwhile,partial deletion of salt bridges in the H187R and double mutants allows the sub-structural domains of the prion protein to separate,which would accelerate the conversion from PrPC to PrPSc.A similar trend is observed in both SASA and Rg for all three mutations,indicating that the conformational space is reduced and the structure is compact.展开更多
The radiation damage of adenine base was studied by B3LYP and MP2 methods in the presence of hydroxyl radicals to probe the reactivities of five possible sites of an isolated adenine molecule. Both methods predict tha...The radiation damage of adenine base was studied by B3LYP and MP2 methods in the presence of hydroxyl radicals to probe the reactivities of five possible sites of an isolated adenine molecule. Both methods predict that the C8 site is the more vulnerable than the other sites. For its bonding covalently with the hydroxyl radicals, B3LYP predicts a barrierless pathway, while MP2 finds a transition state with an energy of 106.1 kJ/mol. For the hydroxylation at the C2 site, the barrier was calculated to be 165.3 kJ/mol using MP2 method. For the dehydrogenation reactions at five sites of adenine, B3LYP method predicts that the free energy barrier decreases in the order of H8 〉 H2 〉 HN62 〉 HN61 〉 HN9.展开更多
For a non-relativistic particle that freely moves on a curved surface, the fundamental commutation relations between positions and momenta are insufficient to uniquely determine the operator form of the momenta. With ...For a non-relativistic particle that freely moves on a curved surface, the fundamental commutation relations between positions and momenta are insufficient to uniquely determine the operator form of the momenta. With introduc- tion of more commutation relations between positions and Hamiltonian and those between momenta and Hamiltonian, our recent sequential studies imply that the Cartesian system of coordinates is physically preferable, consistent with Dirae＇s observation. In present paper, we study quantization problem of the motion constrained on the two-dimensional sphere and develop a discriminant that can be used to show how the quantization within the intrinsic geometry is im- proper. Two kinds of parameterization of the spherical surface are explicitly invoked to investigate the quantization problem within the intrinsic geometry.展开更多
Recently,there are two independent approaches related to a class of nonlinear Lie algebras of three generators;and the realizations of these generators are achieved respectively in Schwinger-boson and position represe...Recently,there are two independent approaches related to a class of nonlinear Lie algebras of three generators;and the realizations of these generators are achieved respectively in Schwinger-boson and position representation.However,by use of the representation transformation between these two representations,the equivalence of the two realizations is therefore proved.展开更多
A technique of coordinate transformation is devised to overcome the computational difficulty associated with the direct transformation between eigenfunctions of three components of the geometric momentum on two-dimens...A technique of coordinate transformation is devised to overcome the computational difficulty associated with the direct transformation between eigenfunctions of three components of the geometric momentum on two-dimensional spherical surface, and the computations are firstly carried out in new coordinates and secondly the results are transformed back into the original coordinates. The eigenfunctions of different components of geometric momentum is explicitly demonstrated to transform under the spatial rotations in the precise way we anticipate.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.52073128,12164002,and 11964012)the Foundation of Educational Committee of Jiangxi Province of China (Grant No.GJJ211112)the Fund for Distinguished Young Scholars of Jiangxi Science&Technology Normal University (Grant No.2015QNBJRC002)。
文摘Prion diseases are a class of fatal neurodegenerative diseases caused by misfolded prion proteins.The main reason is that pathogenic prion protein has a strong tendency to aggregate,which easily induces the damage to the central nervous system.Point mutations in the human prion protein gene can cause prion diseases such as Creutzfeldt-Jakob and Gerstmann's syndrome.To understand the mechanism of mutation-induced prion protein aggregation,the mutants in an aqueous solution are studied by molecular dynamics simulations,including the wild type,V180I,H187R and a double point mutation which is associated with CJD and GSS.After running simulations for 500 ns,the results show that these three mutations have different effects on the kinetic properties of PrP.The high fluctuations around the N-terminal residues of helix 2 in the V180I variant lead to a decrease in hydrogen bonding on helix 2,while an increase in the number of hydrogen bonds between the folded regions promotes the generation ofβ-sheet.Meanwhile,partial deletion of salt bridges in the H187R and double mutants allows the sub-structural domains of the prion protein to separate,which would accelerate the conversion from PrPC to PrPSc.A similar trend is observed in both SASA and Rg for all three mutations,indicating that the conformational space is reduced and the structure is compact.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11564015 and 61404062)the Research Fund for the Doctoral Program of China(Grant No.3000990110)the Fund for Distinguished Young Scholars of Jiangxi Science&Technology Normal University(Grant Nos.2015QNBJRC002 and 2016QNBJRC006)
文摘The radiation damage of adenine base was studied by B3LYP and MP2 methods in the presence of hydroxyl radicals to probe the reactivities of five possible sites of an isolated adenine molecule. Both methods predict that the C8 site is the more vulnerable than the other sites. For its bonding covalently with the hydroxyl radicals, B3LYP predicts a barrierless pathway, while MP2 finds a transition state with an energy of 106.1 kJ/mol. For the hydroxylation at the C2 site, the barrier was calculated to be 165.3 kJ/mol using MP2 method. For the dehydrogenation reactions at five sites of adenine, B3LYP method predicts that the free energy barrier decreases in the order of H8 〉 H2 〉 HN62 〉 HN61 〉 HN9.
基金Supported by the National Natural Science Foundation of China under Grant No.11175063
文摘For a non-relativistic particle that freely moves on a curved surface, the fundamental commutation relations between positions and momenta are insufficient to uniquely determine the operator form of the momenta. With introduc- tion of more commutation relations between positions and Hamiltonian and those between momenta and Hamiltonian, our recent sequential studies imply that the Cartesian system of coordinates is physically preferable, consistent with Dirae＇s observation. In present paper, we study quantization problem of the motion constrained on the two-dimensional sphere and develop a discriminant that can be used to show how the quantization within the intrinsic geometry is im- proper. Two kinds of parameterization of the spherical surface are explicitly invoked to investigate the quantization problem within the intrinsic geometry.
基金Supported by National Natural Science Foundation of China under Grant No. 11175063
文摘Recently,there are two independent approaches related to a class of nonlinear Lie algebras of three generators;and the realizations of these generators are achieved respectively in Schwinger-boson and position representation.However,by use of the representation transformation between these two representations,the equivalence of the two realizations is therefore proved.
基金Supported by National Natural Science Foundation of China under Grant No. 11175063
文摘A technique of coordinate transformation is devised to overcome the computational difficulty associated with the direct transformation between eigenfunctions of three components of the geometric momentum on two-dimensional spherical surface, and the computations are firstly carried out in new coordinates and secondly the results are transformed back into the original coordinates. The eigenfunctions of different components of geometric momentum is explicitly demonstrated to transform under the spatial rotations in the precise way we anticipate.
