An antitumour complex,cis-diammineplatinum(Ⅱ)ascorbate,has been synthesized and its X-ray structure is given.Quantum chemistry calculation compared with its diaminecyclohexane derivatives indicates that they have dif...An antitumour complex,cis-diammineplatinum(Ⅱ)ascorbate,has been synthesized and its X-ray structure is given.Quantum chemistry calculation compared with its diaminecyclohexane derivatives indicates that they have different electron distribution.展开更多
The three-dimensional structure of trichosanthin at 2.7A resolution has been improved further, by refitting one of the C-terminal tails, adjusting 16 residues in the molecular surface regions, discarding some water mo...The three-dimensional structure of trichosanthin at 2.7A resolution has been improved further, by refitting one of the C-terminal tails, adjusting 16 residues in the molecular surface regions, discarding some water molecules with high B values, and adjusting weights during the further refinement. The R-factor has been reduced to 18.5% and the r.m.s deviations from ideal geometry are also improved. The structures of the two molecules in the monoclinic asymmetric unit and the only molecule in the orthorhombic asymmetric unit are compared with one another. The main-chain structures for most of the residues in the three molecules are substantially the same. However, the courses of the three C-terminal tails are completely different, and the intermolecular interactions resulting from the particular packing of the molecules in the crystals account for the differences. The strand Be-2 and the preceding B-turn in small domain show large r.m.s. deviations among the three molecules and they are also involved in intermolecular interactions.展开更多
Complex(n-Bu_4N)[Mo_2O_2(OMe)(mp)_3][1,mp=(o-OC_(?)H_4S)^(2-)]was synthesized by the reaction of MoOCl_3(THF)_2 and Na_2mp in EtOH and crystallized in monoclinic space group P2_(?)/n with crystal data:a=13.910(3),b=23...Complex(n-Bu_4N)[Mo_2O_2(OMe)(mp)_3][1,mp=(o-OC_(?)H_4S)^(2-)]was synthesized by the reaction of MoOCl_3(THF)_2 and Na_2mp in EtOH and crystallized in monoclinic space group P2_(?)/n with crystal data:a=13.910(3),b=23.554(3),c=12.558(2)(?),β=105.20(2)°,Z=4,D_o=1.455g/ cm^3,final R=0.077 for 5325 reflections[I>3σ(I)].The two[Mo(O)mp]^+ moicties are bridged by one 1,2-bidentate ligand mp^(2-) with exceedingly small bite angle(69.0°)and bite distance (2.70(?))and by a methoxy group.The structure can be interpreted as two distorted octahedra around the Mo atoms sharing a face.Attempts have been made to provide structural informa- tions for the syntheses of modelling compounds of FeMoco by comparing the Mo—O and Mo—S bond distances of o-mercaptophenolate ligated compounds to those of the molybdenum site of nitrogenase.展开更多
基金suported by the Medicine and Drug Bureau of China
文摘An antitumour complex,cis-diammineplatinum(Ⅱ)ascorbate,has been synthesized and its X-ray structure is given.Quantum chemistry calculation compared with its diaminecyclohexane derivatives indicates that they have different electron distribution.
文摘The three-dimensional structure of trichosanthin at 2.7A resolution has been improved further, by refitting one of the C-terminal tails, adjusting 16 residues in the molecular surface regions, discarding some water molecules with high B values, and adjusting weights during the further refinement. The R-factor has been reduced to 18.5% and the r.m.s deviations from ideal geometry are also improved. The structures of the two molecules in the monoclinic asymmetric unit and the only molecule in the orthorhombic asymmetric unit are compared with one another. The main-chain structures for most of the residues in the three molecules are substantially the same. However, the courses of the three C-terminal tails are completely different, and the intermolecular interactions resulting from the particular packing of the molecules in the crystals account for the differences. The strand Be-2 and the preceding B-turn in small domain show large r.m.s. deviations among the three molecules and they are also involved in intermolecular interactions.
基金Project supported by the National Natural Science Foundation of Chinathe Natural Science Foundation of the Chinese Academy of Sciences the Natural Science Foundation of Fujian Province.
文摘Complex(n-Bu_4N)[Mo_2O_2(OMe)(mp)_3][1,mp=(o-OC_(?)H_4S)^(2-)]was synthesized by the reaction of MoOCl_3(THF)_2 and Na_2mp in EtOH and crystallized in monoclinic space group P2_(?)/n with crystal data:a=13.910(3),b=23.554(3),c=12.558(2)(?),β=105.20(2)°,Z=4,D_o=1.455g/ cm^3,final R=0.077 for 5325 reflections[I>3σ(I)].The two[Mo(O)mp]^+ moicties are bridged by one 1,2-bidentate ligand mp^(2-) with exceedingly small bite angle(69.0°)and bite distance (2.70(?))and by a methoxy group.The structure can be interpreted as two distorted octahedra around the Mo atoms sharing a face.Attempts have been made to provide structural informa- tions for the syntheses of modelling compounds of FeMoco by comparing the Mo—O and Mo—S bond distances of o-mercaptophenolate ligated compounds to those of the molybdenum site of nitrogenase.
