The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 7...The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I>2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.展开更多
A mononuclear chiral copper（ll） complex, [Cu（RRchxn）2（C（CN）3）2]＇H20 （RRchxn = （1R, 2R）-diaminocyclohexane） （RRchxnH）, and its deuterated compound, [Cu（RRchxn）2（C（CN）3）z].D20 （RRchxnD）, and their...A mononuclear chiral copper（ll） complex, [Cu（RRchxn）2（C（CN）3）2]＇H20 （RRchxn = （1R, 2R）-diaminocyclohexane） （RRchxnH）, and its deuterated compound, [Cu（RRchxn）2（C（CN）3）z].D20 （RRchxnD）, and their isomers, [Cu（trchxn）2（C（CN）3）2]＇H20 （trchxn = trans-l,2-diaminocyclohexane） （trchxnH） and [Cu（trchxn）2（C（CN）3）2]＇D20 （trchxnD） have been prepared and characterized by means of 1R （infrared）, electronic, and CD （circular dichroism） spectra, magnetic susceptibility, and variable-temperature X-ray crystallography as single crystals or powder. Interestingly, depending on grain size of samples, RRchxnH exhibits the monoclinic form and the orthorhombic form, which are distinguished by systematic absence and powder XRD （X-ray diffraction） patterns clearly. Although single crystals did not exhibit phase transition, powder XRD patterns of RRchxnH and weakly hydrogen bonded RRchxnD emerged low-temperature phase of monoclinic in the orthorhombic patterns only around 200-220 K. However, as a control, powder XRD patterns of both trchxnH and trchxnD did not exhibit such phase transition clearly.展开更多
Viruses in the family Reoviridae are non-enveloped particles comprising a segmented double-stranded RNA genome surrounded by a two-layered or multi-layered icosahedral protein capsid.These viruses are classified into ...Viruses in the family Reoviridae are non-enveloped particles comprising a segmented double-stranded RNA genome surrounded by a two-layered or multi-layered icosahedral protein capsid.These viruses are classified into two sub-families based on their particle structural organization.Recent studies have focused on high-resolution three-dimensional structures of reovirus particles by using cryo-electron microscopy (cryo-EM) to approach the resolutions seen in X-ray crystallographic structures.The results of cryo-EM image reconstructions allow tracing of most of the protein side chains,and thus permit integration of structural and functional information into a coherent mechanism for reovirus assembly and entry.展开更多
NMR spectroscopy and X-ray crystallography are two premium methods for determining the atomic structures of macro-biomolecular complexes.Each method has unique strengths and weaknesses.While the two techniques are hig...NMR spectroscopy and X-ray crystallography are two premium methods for determining the atomic structures of macro-biomolecular complexes.Each method has unique strengths and weaknesses.While the two techniques are highly complementary,they have generally been used separately to address the structure and functions of biomolecular complexes.In this review,we emphasize that the combination of NMR spectroscopy and X-ray crystallography offers unique power for elucidating the structures of complicated protein assemblies.We demonstrate,using several recent examples from our own laboratory,that the exquisite sensitivity of NMR spectroscopy in detecting the conformational properties of individual atoms in proteins and their complexes,without any prior knowledge of conformation,is highly valuable for obtaining the high quality crystals necessary for structure determination by X-ray crystallography.Thus NMR spectroscopy,in addition to answering many unique structural biology questions that can be addressed specifically by that technique,can be exceedingly powerful in modern structural biology when combined with other techniques including X-ray crystallography and cryo-electron microscopy.展开更多
A series of lanthanide complexes with the 3,4,5-trimethoxybenzoic acid （3,4,5-tmoba） and 1,10-phenanthroline（phen）, [Ln（3,4,5-tmoba）3phen]2（Ln = Pr（l）, Nd （2） and Ho（3））, have been synthesized and charac...A series of lanthanide complexes with the 3,4,5-trimethoxybenzoic acid （3,4,5-tmoba） and 1,10-phenanthroline（phen）, [Ln（3,4,5-tmoba）3phen]2（Ln = Pr（l）, Nd （2） and Ho（3））, have been synthesized and characterized by a series of techniques including elemental analysis, IR spectra, X-ray crystallography and TG/DSC-FTIR technology. The three complexes have two kinds of coordination modes, in which the Pr3＋ and Nd3＋ cations are nine-coordinated and the Ho3＋ cation is eight-coordinated. The three-dimensional IR accumulation spectra of gaseous products for complexes 1-3 were analyzed and the gaseous products were identified by the typical IR spectra obtained from the 3D surface graphs. Meanwhile, we obtained the activation energy E of the first steps of complexes 1-3 by the integral isoconversional non-linear （NL-INT） method and discussed the non-isothermal kinetics of complexes 1-3 using the Malek method. Finally, SB（m, n） was defined as the kinetic method of the first-step thermal decomposition. The thermodynamic parameters △G≠, △H≠ and △S≠ of activation at the peak temperature were also calculated.展开更多
利用电子显微镜首次拍到DNA照片
意大利卡坦扎罗马格纳一格雷沙大学的Enzo di Fabdzio等利用电子显微镜拍到这种支持生命的螺旋梯形结构的第一张直接照片，这是第一次发现这种双螺旋结构采用的是X射线结晶学技术，这项技术根据X射线遇...利用电子显微镜首次拍到DNA照片
意大利卡坦扎罗马格纳一格雷沙大学的Enzo di Fabdzio等利用电子显微镜拍到这种支持生命的螺旋梯形结构的第一张直接照片，这是第一次发现这种双螺旋结构采用的是X射线结晶学技术，这项技术根据X射线遇到物质后被反弹回来的模式，重建它的结构。展开更多
文摘The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I>2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.
文摘A mononuclear chiral copper（ll） complex, [Cu（RRchxn）2（C（CN）3）2]＇H20 （RRchxn = （1R, 2R）-diaminocyclohexane） （RRchxnH）, and its deuterated compound, [Cu（RRchxn）2（C（CN）3）z].D20 （RRchxnD）, and their isomers, [Cu（trchxn）2（C（CN）3）2]＇H20 （trchxn = trans-l,2-diaminocyclohexane） （trchxnH） and [Cu（trchxn）2（C（CN）3）2]＇D20 （trchxnD） have been prepared and characterized by means of 1R （infrared）, electronic, and CD （circular dichroism） spectra, magnetic susceptibility, and variable-temperature X-ray crystallography as single crystals or powder. Interestingly, depending on grain size of samples, RRchxnH exhibits the monoclinic form and the orthorhombic form, which are distinguished by systematic absence and powder XRD （X-ray diffraction） patterns clearly. Although single crystals did not exhibit phase transition, powder XRD patterns of RRchxnH and weakly hydrogen bonded RRchxnD emerged low-temperature phase of monoclinic in the orthorhombic patterns only around 200-220 K. However, as a control, powder XRD patterns of both trchxnH and trchxnD did not exhibit such phase transition clearly.
基金supported by grants from the National Natural Science Foundation of China(31172434,31372565)
文摘Viruses in the family Reoviridae are non-enveloped particles comprising a segmented double-stranded RNA genome surrounded by a two-layered or multi-layered icosahedral protein capsid.These viruses are classified into two sub-families based on their particle structural organization.Recent studies have focused on high-resolution three-dimensional structures of reovirus particles by using cryo-electron microscopy (cryo-EM) to approach the resolutions seen in X-ray crystallographic structures.The results of cryo-EM image reconstructions allow tracing of most of the protein side chains,and thus permit integration of structural and functional information into a coherent mechanism for reovirus assembly and entry.
基金supported by grants from the Research Grants Council of Hong Kong to M.Z.supported by the National Major Basic Research Program of China (Grant No. 2011CB910500)+3 种基金the National Natural Science Foundation of China (Grant No. 31070657)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KSCX2-YW-R-154)The NMR spectrometers used in our studies were funded by donations from the Hong Kong Jockey Club Charity Foundationthe Special Equipment Grant from RGC of Hong Kong (Grant No. SEG_HKUST06)
文摘NMR spectroscopy and X-ray crystallography are two premium methods for determining the atomic structures of macro-biomolecular complexes.Each method has unique strengths and weaknesses.While the two techniques are highly complementary,they have generally been used separately to address the structure and functions of biomolecular complexes.In this review,we emphasize that the combination of NMR spectroscopy and X-ray crystallography offers unique power for elucidating the structures of complicated protein assemblies.We demonstrate,using several recent examples from our own laboratory,that the exquisite sensitivity of NMR spectroscopy in detecting the conformational properties of individual atoms in proteins and their complexes,without any prior knowledge of conformation,is highly valuable for obtaining the high quality crystals necessary for structure determination by X-ray crystallography.Thus NMR spectroscopy,in addition to answering many unique structural biology questions that can be addressed specifically by that technique,can be exceedingly powerful in modern structural biology when combined with other techniques including X-ray crystallography and cryo-electron microscopy.
基金the National Natural Science Foundation of China (21073053,21073052,20773034)the Natural Science Foundation of Hebei Province (B2012205022)
文摘A series of lanthanide complexes with the 3,4,5-trimethoxybenzoic acid （3,4,5-tmoba） and 1,10-phenanthroline（phen）, [Ln（3,4,5-tmoba）3phen]2（Ln = Pr（l）, Nd （2） and Ho（3））, have been synthesized and characterized by a series of techniques including elemental analysis, IR spectra, X-ray crystallography and TG/DSC-FTIR technology. The three complexes have two kinds of coordination modes, in which the Pr3＋ and Nd3＋ cations are nine-coordinated and the Ho3＋ cation is eight-coordinated. The three-dimensional IR accumulation spectra of gaseous products for complexes 1-3 were analyzed and the gaseous products were identified by the typical IR spectra obtained from the 3D surface graphs. Meanwhile, we obtained the activation energy E of the first steps of complexes 1-3 by the integral isoconversional non-linear （NL-INT） method and discussed the non-isothermal kinetics of complexes 1-3 using the Malek method. Finally, SB（m, n） was defined as the kinetic method of the first-step thermal decomposition. The thermodynamic parameters △G≠, △H≠ and △S≠ of activation at the peak temperature were also calculated.
