With density functional theory（DFT） and molecular mechanics method, the catalytic mechanism of silent information regulator（sirtuins） has been investigated. The calculations support the SN2-1ike reaction of the in...With density functional theory（DFT） and molecular mechanics method, the catalytic mechanism of silent information regulator（sirtuins） has been investigated. The calculations support the SN2-1ike reaction of the initial step of the catalysis, and are consistent with experiment results. We further explored the second step of the catalysis and proposed that this step took place in a concerted reaction. In addition, the side chain of Phenylalanine33 may help to shield the glycosidic bond from water and be in a position to protect the developing oxacabenium transition state from hydrolysis. Our results of the calculations support this hypothesis that the phenylalanine33 plays a critical role in the sirtuins biology function.展开更多
Glutathione transferases（GSTs） play an important role in the detoxification of xenobiotic/endobiotic toxic compounds. The α-, π-, and/l-classes of cytosolic GSTs have been studied extensively, while Gtt2 from Sacc...Glutathione transferases（GSTs） play an important role in the detoxification of xenobiotic/endobiotic toxic compounds. The α-, π-, and/l-classes of cytosolic GSTs have been studied extensively, while Gtt2 from Saccharo- myces cerevisiae, a novel atypical GST, is still poorly understood. In the present study, we investigated the gluta- thione（GSH） activation mechanism of Gtt2 using the density functional theory（DFT） with the hybrid functional B3LYP. The computational results show that a water molecule could assist a proton transfer between the GSH thiol and the N atom of His133. The energy barrier of proton transfer is 46.0 kJ/mol. The GSH activation mechanism and the characteristics of active site are different from those of classic cytosolic GSTs.展开更多
Two novel compounds（4a and 4b） were obtained by the association of 2,2,4-trimethyl-3-hydroxy-5-cyclohexenecarboxylate with （S） -isoserine derivatives. The space location of the hydroxyl group of compound 1 was ide...Two novel compounds（4a and 4b） were obtained by the association of 2,2,4-trimethyl-3-hydroxy-5-cyclohexenecarboxylate with （S） -isoserine derivatives. The space location of the hydroxyl group of compound 1 was identified via the formation of lactone 6. Fe2 （SO4）3·xH2O was used as the catalyst for the synthesis of lactone 6. The carboxyl group was selectively protected with diazomethane. All the products were characterized via ^1H NMR and mass spectra. The Docking study showed that the associations have the potential therapeutic use of DPP-Ⅳ inhibitor.展开更多
A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru（dcbpyH2）2（NCS）2]（N3,dcbpy=4,4＇-dicarboxy2,2...A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru（dcbpyH2）2（NCS）2]（N3,dcbpy=4,4＇-dicarboxy2,2＇-bipyridine;NCS=thiocyanato）.Density functional theory（DFT） based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT（TD-DFT） results indicate that the ancillary ligand dominates the molecular orbital（MO） energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO（HOMO） to the lowest unoccupied MO（LUMO） and LUMO to LUMO＋1 orbital.If the gap between LUMO-LUMO＋1 is small enough,the higher efficiency of dye-sensitized solar cell（DSSC） should be expected.展开更多
基金Supported by the National Natural Science Foundation of China(No.20573042, 20903045)Specialized Research Fund forthe Doctoral Program of Higher Education of China(No.20070183046) Specialized Fund for the Basic Research of Jilin Uni-versity, China(No.200810018)
文摘With density functional theory（DFT） and molecular mechanics method, the catalytic mechanism of silent information regulator（sirtuins） has been investigated. The calculations support the SN2-1ike reaction of the initial step of the catalysis, and are consistent with experiment results. We further explored the second step of the catalysis and proposed that this step took place in a concerted reaction. In addition, the side chain of Phenylalanine33 may help to shield the glycosidic bond from water and be in a position to protect the developing oxacabenium transition state from hydrolysis. Our results of the calculations support this hypothesis that the phenylalanine33 plays a critical role in the sirtuins biology function.
基金Supported by the National Natural Science Foundation of China(No.20903045)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20070183046)the Specialized Fund for the Basic Research of Jilin University,China(No.200810018)
文摘Glutathione transferases（GSTs） play an important role in the detoxification of xenobiotic/endobiotic toxic compounds. The α-, π-, and/l-classes of cytosolic GSTs have been studied extensively, while Gtt2 from Saccharo- myces cerevisiae, a novel atypical GST, is still poorly understood. In the present study, we investigated the gluta- thione（GSH） activation mechanism of Gtt2 using the density functional theory（DFT） with the hybrid functional B3LYP. The computational results show that a water molecule could assist a proton transfer between the GSH thiol and the N atom of His133. The energy barrier of proton transfer is 46.0 kJ/mol. The GSH activation mechanism and the characteristics of active site are different from those of classic cytosolic GSTs.
基金Supported by the National Natural Science Foundation of China(No. 20172019)
文摘Two novel compounds（4a and 4b） were obtained by the association of 2,2,4-trimethyl-3-hydroxy-5-cyclohexenecarboxylate with （S） -isoserine derivatives. The space location of the hydroxyl group of compound 1 was identified via the formation of lactone 6. Fe2 （SO4）3·xH2O was used as the catalyst for the synthesis of lactone 6. The carboxyl group was selectively protected with diazomethane. All the products were characterized via ^1H NMR and mass spectra. The Docking study showed that the associations have the potential therapeutic use of DPP-Ⅳ inhibitor.
基金Supported by the National Natural Science Foundation of China(Nos.20973076,21003057)the Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20110061110018)
文摘A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru（dcbpyH2）2（NCS）2]（N3,dcbpy=4,4＇-dicarboxy2,2＇-bipyridine;NCS=thiocyanato）.Density functional theory（DFT） based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT（TD-DFT） results indicate that the ancillary ligand dominates the molecular orbital（MO） energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO（HOMO） to the lowest unoccupied MO（LUMO） and LUMO to LUMO＋1 orbital.If the gap between LUMO-LUMO＋1 is small enough,the higher efficiency of dye-sensitized solar cell（DSSC） should be expected.
