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TMK:A crucial piece of the acid growth puzzle

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molecular Plant 2021年第12期14卷 1982-1984页

作者： Yakun Peng Shutang Tan MOE Key Laboratory for Cellular Dynamics Division of Molecular&Cell BiophysicsHefei National Science Center for Physical Sciences at the Microscaleand School of Life SciencesDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230027China

Plant cells have relatively high turgor pressure driving cell expan-sion,which is restricted by the cell *** plant cells grow in an intrinsically controlled manner is an intriguing question,and the phytohormone auxin(indole-3-acetic acid,IAA)plays a vital reg-ulatory *** auxin-mediated acid growth theory was pro-posed decades ago,whereas the underlying mechanisms were not fully *** membrane(PM)H+-ATPases,also called Arabidopsis AUTOINHIBITED H+ATPASEs(AHAs),are proton pumps majorly responsible for regulating cell growth in *** on our current understandings of the acid growth theory,auxin stimulates AHA proteins and thus promotes proton(H+)efflux,which thereby acidifies the apoplast to activate cell wall-modifying enzymes,such as expansins,eventually softening the cell wall to accommodate cell expansion(Duet al.,2020).Activated AHA proteins also cause PM hyperpolarization,enabling solute and water uptake to increase turgor pressure driving cell expansion(Duet al.,2020).Hence,how auxin activates PM H^(+)-ATPases is central to the acid growth ***,that was until now not fully understood.

关键词： driving eventually thereby

Synthesis and Crystal Structure of 3-Benzoyl-7,7-dimethyl-4-phenyl-2-phenylamino-4,6,7,8-tetrahydro-chromen-5-one

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Chinese Journal of Structural Chemistry 2007年第4期26卷 385-388页

作者：李明孙恩涛文丽荣王书文 College of Chemistry and molecular Engineering Qingdao University of Science and Technology

The title compound （C30H27NO3） was synthesized via a one-pot procedure starting from fl-benzoylthioacetanilide, benzaldehyde and 5,5-dimethyl-1,3-cyclohexanedione, and its structure was determined by single-crystal X-ray diffraction analysis. The crystal belongs to triclinic system, space group PI, with a = 6.325（2）, b = 11.243（3）, c = 17.553（4） A, a = 87.306（4）, β = 80.822（4）, γ = 77.798（4）°, V= 1204.2（5） A^3, Z = 2, Mr= 449.53, Dc= 1.240 g/cm^3, p = 0.080 mm^-1, F（000） = 476, the final R = 0.0459 and wR = 0.0970 for 2301 observed reflections with I 〉 2σ（I）.

关键词： tetrahydrochromene thioamides MCRs crystal structure

Kinetics of energy transfer processes in C-phycocyanin complexes

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science China Chemistry 1999年第5期42卷 485-492页

作者：赵井泉李晔 Centre for molecular science Institute of Chemistry Beijing China

The antenna system of algae for photosynthesis is a functional entity composed of various phycobiliproteins and the linker polypeptides. Up to now, high-resolution crystal structure data have been available only for the isolated phycohiliproteins. To have an understanding of the functional connection between different phycobiliproteins, it is necessary to study the complexes composed of different phycobiliproteins. The energy transfer processes in C-phycocyanin complexes were studied through computer simulation because it is dificult to be studied by conventional experimental methods. The main pathways of energy flow and the dynamic property of the energy transfer were obtained. A fast transfer process between two neighboring disks was observed through analyzing the distribution curves of excitation energy over time. According to the definition of the time constants for energy transfer in time-resolved spectrum techniques, for a complex with three C-phycocyanin hexamer disks, a fluorescence-rising component with several picoseconds was obtained in disk 2 and 20 ps in disk 3 when the chromophores in disk 1 were excited by an ideal Δ pulsed laser beam. The results showed clearly that the energy transfer between the disks in an antenna rod was very fast and that energy transfer was fast and efficient in an intact antenna system of algae.

关键词： C-phycocyanin complex computer simulation energy transfer kinetics.

molecular modeling on Zn(II) binding modes of Alzheimer's amyloid β-peptide in insoluble aggregates and soluble complexes

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science China Chemistry 2004年第2期47卷 126-133页

作者： HAN Daxiong YANG Pin Institute of molecular science Chemical Biology and Molecular Engineering Laboratory of Ministry of Education Shanxi University Taiyuan 030006 China Institute of Molecular Science Chemical Biology and Molecular Engineering Laboratory of Ministry of Education Shanxi University Taiyuan 030006 China

Aggregation of the amyloid b-peptide (A b) into insoluble fibrils is a key pathologi-cal event in Alzheimers disease. Zn(II) ion induces significant Ab aggregation at nearly physio-logical concentrations in vitro. In order to explore the induce mechanism, the possible binding modes of Zn(II) in Ab peptide are studied by molecular modeling method. First, the Ab species containing 1,2,4 and 12 peptides are established respectively. And next a Zn(II) ion is manually hold the different sits of the Ab species based on the experimental data and subsequently the coordinate atom and number are assigned. Finally, the optimum binding site is found by the system energy minimization. Modeling results show that in soluble Zn(II) complex, Nt of imidazole ring of His14, O of carbonyl of main-chain, and two O of water occupy the four ligand positions of the tetrahedral complex; in the aggregation of Ab, the His13(Nt)-Zn(II)-His14(Nt) bridges are formed by Zn(II) cross-linking action. Therefore, the possible Zn(II) binding mode obtained by the studies will be helpful to reveal the form mechanism of pathogenic aggregates in brain.

关键词： molecular modeling amyloid b-peptide Zn(II) binding mode Alzheimers disease.

Syntheses, Structures, and Luminescence Properties of Two New Open-framework Zinc Phosphites Based on 1,2,4-Triazole Derivatives

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Chinese Journal of Structural Chemistry 2018年第8期37卷 1331-1338页

作者：闫娟枝卢丽萍 Institute of molecular science Shanxi University Taiyuan University

With 1,2,4-triazole derivatives as structure directing agents, two new openframework zinc phosphites, [Zn（atrz）（HPO3）]n（1） and [Zn（dmatrz）（HPO3）]n（2）（atrz = 4-amino-1,2,4-triazole, dmatrz = 4-amino-3,5-dimethyl-1,2,4-triazole） have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Both compounds are isostructure and crystallize in the P21/c space group of monoclinic system. Compound 1： a = 9.629（1）, b = 7.384（1）, c = 10.274（1） A, β = 110.729（3）°, V = 683.26（2） A^3, Z = 4, Mr = 229.44, Dc = 2.230 g/cm^3, F（000） = 456, S = 1.10, μ = 3.79 mm^（–1）, R = 0.0181 and w R = 0.0466 for 1121 observed reflections（（40）〉 2s（（40）））. Compound 2： a = 10.786（2）, b = 8.921（1）, c = 9.749（1） A, β = 107.3°, V = 895.6（3） A^3, Z = 4, Mr = 257.49, Dc = 1.910 g/cm^3, F（000） = 520, S = 1.00, μ = 2.90 mm^（–1）, R = 0.018 and wR = 0.051 for 1581 observed reflections（（40）〉 2s（（40）））. Both compounds are built up into 4.8-net 2D open-frameworks of vertex-linked Zn O4 and HPO3 units（3.57 × 4.53 A^2 for 1 and 4.43 × 5.90 A^2 for 2）. The structures consist of left-, right-handed helical chains that are connected through oxygen atoms to form an undulated 2D sheet stack, which can be topologically regarded as 4.8~2 nets. Solid-state luminescence properties and thermo gravimetric analyses of these two compounds were investigated, respectively.

关键词： zinc phosphites 1 2 4-triazole structure luminescence property

SMALL ANGLE LIGHT SCATTERING MEASUREMENT OF THE ISOTROPIC TO NEMATIC TRANSITION OF A SIDE CHAIN NEMATIC POLYMETHACRYLATE

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Chinese Journal of Polymer science 2002年第5期20卷 431-437页

作者： Zhong-ming Hu Ren-yuan Qian Shou-xi Chen Xiao-fang Chen Qi-feng Zhou Centre for molecular science, Institute of Chemistry Chinese Academy of sciences, Beijing 100080, China Department of Polymer science & Engineering College of Chemistry & molecular Engineering Peking University Beijing 100871, China Centre for molecular science Institute of Chemistry Chinese Academy of Sciences 北京 100080 Department of Polymer science & Engineering College of Chemistry & Molecular Engineering Peking University 北京 100871

The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows the transition temperatures K52N79I in degreesC, The H-v scattering intensity T(q,t) during the transition I (at 80.2degreesC)-->N (at 75.8degreesC) shows that T(q) is independent of q for all t, and during the initial stage (in 6 s) T(t) increases exponentially with t. In the later stage of the transition T(t) approaches a saturation value in 2 min. This experimental result indicates that the I-->N transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.

关键词： side chain nematic polymer isotropic-nematic transition small angle depolarized light scattering

THE SPATIAL DISTRIBUTION AND MOMENTS OF CIRCULAR FREELY JOINTED CHAIN

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Chinese Journal of Polymer science 1991年第2期9卷 101-107页

作者：郝鸣鸿 Institute of molecular science Shanxi University Taiyuan Shanxi

The spatial distribution function and second moments of circular freely jointed chain are derived based on an analytical method. The circular Gauss chain, which is simple for long chains, is compared with the circular freely jointed chain, which is exact for short chains. It is shown that the Gauss chain model predicts a more compact configurational distribution than the exact freely jointed chain. The two chain models, however, become closer to each other when the chain length increases. It is found that the difference of the mean square radius of gyration calculated with these two chain models is a constant, independent of the chain length.

关键词： Freely Jointed Chain Gauss Chain Spatial Distribution

Physical,Mechanical,and Tribological Attributes of Stir-Cast AZ91/SiC_p Composite

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Acta Metallurgica Sinica(English Letters) 2014年第2期27卷 295-305页

作者： K.K.Ajith Kumar Abhilash Viswanath T.P.D.Rajan U.T.S.Pillai B.C.Pai Material science and Technology division CSIR-National Institute for Interdisciplinary Science and Technology

In the present investigation, composites with silicon carbide particle （SiCp） as reinforcement and AZ91 magnesium alloy as matrix have been synthesized using liquid metal stir-casting technique with optimized processing conditions. The composites with good particle distribution in the matrix, and better grain refinement and good interfacial bonding between the matrix and reinforcement have been obtained. The effect of SiCp content on the physical, mechanical, and tribological properties of Mg-based metal matrix composite （MMC） is studied with respect to particle distribution, grain refinement, and particle/matrix interfacial reactions. The electrical conductivity, coefficient of thermal expansion, microas well as macro-hardness, tensile and compressive properties, and the fracture behavior of the composites along with dry sliding wear of the composites have been evaluated and compared with the base alloy.

关键词： Composite AZ91D alloy Casting alloy Mechanical properties Wear

Synthesis and Crystal Structure of 1′-Methyl-4′- (4-chlorophenyl)-1H-indole-3-spiro-2′-pyrrolidine- 3′-spiro-4''-(2''-phenyloxazole)-2,5''(3H,4''H)-dione

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Chinese Journal of Structural Chemistry 2008年第1期27卷 88-92页

作者：文丽荣刘鹏李明 College of Chemistry and molecular Engineering Qingdao University of Science and Technology

The title compound （C26H20ClN3O3） has been synthesized by 1,3-dipolar cycloaddition reaction from isatin, sarcosine and （Z）-4-（4-chlorobenzylidene）-2-phenyloxazol-5（4H）-one through a one-pot procedure, and its structure was confirmed by IR, IH NMR, elemental analysis and single-crystal X-ray diffraction analysis. The crystal belongs to the triclinic system, space group PI, with a = 9.3903（19）, b = 11.398（2）, c = 12.603（3） A, α = 83.495（3）, β = 68.988（3）, γ = 67.178（3）^o, V= 1160.1（4）A^3 Z = 2, Mr= 457.90, Dc= 1.311 g/cm^3, p = 0.198 mm ^-1, F（000） = 476, the final R = 0.0489 and wR = 0.1144 for 3109 observed reflections with I 〉 2σ（I）.

关键词： isatin oxazolidinone 1,3-dipolar cydoaddition MCRs crystal structure