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Methanol as a probe to investigate the relationship between the secondary electron donor TyrZ and the substrate water molecules in active photosystem Ⅱ

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chinese Science Bulletin 2010年第9期55卷 809-813页

作者： BAO Han, ZHANG ChunXi, REN YaNan & ZHAO JingQuan Laboratory of Photochemistry, beijing National Laboratory of Molecular sciences, institute of chemistry, chinese academy of sciences, beijing 100190, china Laboratory of Photochemistry Beijing National Laboratory of Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing China

The secondary electron donor, TyrZ, is implicated in tuning the primary charge separation and the water oxidation in active pho-tosystem II (PSII). Two types of mechanisms have been proposed to explain the function of TyrZ. One is that TyrZ tunes the water oxidation through the direct interaction with substrate water molecules; the other is that TyrZ is located in a hydrophobic envi-ronment without interacting with H2O, and controls the water oxidation by tuning the strength of the hydrogen bond between TyrZ and His190. Here, methanol was used as a probe to study the possible relationship between TyrZ and H2O by monitoring the TyrZ oxidation and TyrZ· reduction at cryogenic temperatures with electron paramagnetic resonance spectroscopy. The oxidation of TyrZ and reduction of TyrZ· in both S2 and S0 states at 10 K were accelerated by addition of a small amount of methanol (6%). Theoretical studies indicate that Tyr oxidation becomes more difficult if it interacts directly with the methanol molecule; while the decrease of the polarity of its environment accelerates the oxidation of Tyr. Accordingly, CH3OH does not directly interact with TyrZ in active PSII, and the accelerative effect of methanol is caused by the strength increase of the hydrogen bond between TyrZ and His190, resulting from the decrease of polarity of their environment after the displacement of H2O by CH3OH inside PSII. Considering the similarity between methanol and water, the results in this study support the model in which TyrZ does not interact with H2O in active PSII.

关键词： photosystem Ⅱ secondary electron donor TyrZ methanol water electron paramagnetic resonance

Periodic tables of diatomic and triatomic molecules

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Science china chemistry 2012年第6期55卷 618-625页

作者： KONG FanAo & WU WeiQiang beijing National Laboratory for Molecular sciences, institute of chemistry, chinese academy of sciences, beijing 100190, china 1. beijing National Laboratory for Molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China

The Mendeleev periodic table of atoms is one of the most important principles in natural science. However, there is shortage of analog for molecules. Here we propose two periodic tables, one for diatomic molecules and one for triatomic molecules. The form of the molecular periodic tables is analogous to that of Mendeleev periodic table of atoms. In the table, molecules are classified and arranged by their group number G, which is the number of valence electrons, and the periodic number P, which represents the size of the molecules. The basic molecular properties, including bond length, binding energy, force constant, ionization potential, spin multiplicity, chemical reactivity, and bond angle, change periodically within the tables. The periodicities of diatomic and triatomic molecules are thus revealed. We also demonstrate that the periodicity originates from the shell-like electronic configurations of the molecules. The periodic tables not only contain free molecules, but also the "virtual" molecules present in polyatomic molecules. The periodic tables can be used to classify molecules, to predict unknown molecular properties, to understand the role of virtual molecules in polyatomic molecules, and to initiate new research fields, such as the periodicities of aromatic species, clusters, or nanoparticles. The tables should be of interest not only to scientists in a variety of disciplines, but also to undergraduates studying natural sciences.

关键词： molecular periodicity – periodic table – diatomic molecules – triatomic molecules – molecular property

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Recognition of amino acids and anions by a Zn(Ⅱ)-methylazacalix[4]pyridine complex

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Science china chemistry 2009年第10期52卷 1639-1645页

作者： GONG HanYuan, WANG DeXian, HUANG ZhiTang & WANG MeiXiang beijing National Laboratory for Molecular sciences, CAS Laboratory of Molecular Recognition and Function, institute of chemistry, chinese academy of sciences, beijing 100190, china beijing National Laboratory for Molecular sciences CAS Laboratory of Molecular Recognition and Function Institute of Chemistry Chinese Academy of Sciences Beijing China

As a powerful macrocyclic host molecule with unique conformation and cavity structure that are fine-tuned by the bridging nitrogen atoms, methylazacalix[4]pyridine (MACP-4) has been shown to selectively recognize Zn2+ and form stable Zn(Ⅱ)-MACP-4 complexes both in solid state and solution with an association constant up to 5.97 (logKs). The molecular recognition of Zn(Ⅱ)-MACP-4 complexes towards various amino acids and anions with different geometry was investigated by using the spectral titration methods and X-ray analysis. The Zn(Ⅱ)-MACP-4 complex was found to recognize the 17 amino acids tested with the association constant up to 3.97 (logKs). On the other hand, the Zn(Ⅱ)-MACP-4 complex selectively interacted with anions and the maximum association constant of 3.9 (logKs) was obtained.

关键词： Zn(Ⅱ)-MACP-4 complex amino acids anions recognition

Biodegradable amphiphilic block copolymers containing functionalized PEO blocks:Controlled synthesis and biomedical potentials

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Science china chemistry 2010年第3期53卷 519-527页

作者： ZHANG Yu1,2,SUN PeiJian1,2 & GAN ZhiHua1 1CAS Key Laboratory of Engineering Plastics,institute of chemistry,chinese academy of sciences,beijing 100190,china 2Graduate University of chinese academy of sciences,beijing 100039,china 1. CAS Key Laboratory of Engineering Plastics Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100039 China

A series of controllable amphiphilic block copolymers composed of poly(ethylene oxide)(PEO) as the hydrophilic block and poly(ε-caprolactone)(PCL) as the hydrophobic block with the amino terminal group at the end of the PEO chain(PCL-b-PEO-NH2) were *** on the further reaction of reactive amino groups,diblock copolymers with functional carboxyl groups(PCL-b-PEO-COOH) and functional compounds RGD(PCL-b-PEO-RGD) as well as the triblock copolymers with thermosensitive PNIPAAm blocks(PCL-b-PEO-b-PNIPAAM) were *** well-controlled structures of these copolymers with functional groups and blocks were characterized by gel permeation chromatography(GPC) and 1H NMR *** copolymers with functionalized hydrophilic blocks were fabricated into microspheres for the examination of biofunctions via cell culture experiments and in vitro drug *** results indicated the significance of introducing functional groups(e.g.,NH2,COOH and RGD) into the end of the hydrophilic block of amphiphilic block copolymers for biomedical potentials in tissue engineering and controlled drug release.

关键词： amphiphilic block copolymers biodegradable polymers functional terminal group cell growth drug release

Organic single crystals or crystalline micro/nanostructures: Preparation and field-effect transistor applications

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Science china chemistry 2010年第6期53卷 1225-1234页

作者： FU XiaoLong,WANG ChengLiang,LI RongJin,DONG HuanLi & HU WenPing beijing National Laboratory for Molecular sciences,Key Laboratory of Organic Solids,institute of chemistry,chinese academy of sciences,beijing 100190,china 1. beijing National Laboratory for Molecular sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China

Organic single crystals hold great promise for the development of organic semiconductor materials,because they could reveal the intrinsic electronic properties of these materials,providing high-performance electronic devices and probing the structureproperty *** article reviews the preparation methods for organic single crystals or crystalline micro/nanostructures,including vapor phase growth methods and solution-processed methods,and summarizes a few methods employed in the fabrication of field-effect transistors along with dozens of examples concerning both small molecules and polymers with high field-effect performance.

关键词： organic single crystal physical vapor transport (PVT) solution-processed technique field-effect transistors (FETs) micro/nanostructures

Construction and evaluation of a novel end-column amperometric detection system for electrophoresis microchips

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Science china chemistry 2010年第1期53卷 250-256页

作者： CHEN ZhiFeng1,GAO YunHua2,WANG Li3,CHU XiaoGang1 1chinese academy of Inspection and Quarantine,beijing 100123,china 2Technical institute of Physics and chemistry,chinese academy of sciences,beijing 100190,china 3beijing institute of Labour Protection,beijing 100054,china 1. chinese academy of Inspection and Quarantine Beijing 100123 China2. Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China3. Beijing Institute of Labour Protection Beijing 100054 China

A set of integrated end-column amperometric detection system has been developed,onto which an electrophoresis microchip can be conveniently *** machined by a piece of transparent organic glass,the system consists of an electrophoresis microchip platform and an amperometric detection reservoir,in which the microchip can be fixed onto the platform by microchip grooves and with stainless steel *** detection electrode can be directly fixed in the amperometric detection reservoir by screws and *** dopamine as the model analyte,we take platinum disc electrodes with different diameters of 100 μm,300 μm and 500 μm and a carbon fiber electrode with the diameter of 240 μm as the working electrode,all of which accomplish sensitive *** detection parameters of the system are optimized with the carbon fiber *** detection results show that in the electrochemical cleaning procedure,the relative deviations of 3.2% and 0.5% for the peak current and retention time,respectively,can be obtained for the successive detections of 100 μM dopamine,and the limit of detection for dopamine can reach 0.4 μM(S/N = 3).This system is small,but its performance of detection is stable and sensitive,and the replacement of its working electrodes is convenient,so it is very suitable as a universal platform of end-column amperometric detection for electrophoresis microchips.

关键词： electrophoresis microchip amperometric detection dopamine evaluation

Electron structure and substituent effects in o-,m-,p-IC_6H_4OCH_3 iodoanisoles

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Science china chemistry 2009年第11期52卷 1932-1937页

作者： TONG ShengRui,WANG WeiGang,MA ChunPing,GE MaoFa & WANG DianXun beijing National Laboratory for Molecular sciences(BNLMS),State Key Laboratory for Structural chemistry of Unstable and Stable Species,institute of chemistry,chinese academy of sciences,beijing 100190,china 1. beijing National Laboratory for Molecular sciences (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China

The electronic structures and substituent effects in o-,m-,and p-iodoanisoles have been investigated by ultraviolet photoelectron spectroscopy(UPS).The observed UPS bands were analyzed by combining empirical arguments and theoretical *** to the electron-donating nature of both iodoand methoxy substituents,the first ionization potentials of the three iodoanisoles are lower than those of iodobenzene and *** presence of the two substituents in iodoanisoles leads to an electronrich structure,which might contribute to the observed high reactivity of iodoanisoles in a number of organic reactions.

关键词： electronic structures substituent effects ultraviolet photoelectron spectroscopy reactivity

Formation of super-concentrated hydrochloric acid in the third phase in tertiary amine N235-PtCl_6^(2-)-HCl system and its influences on the Pt microemulsion extraction

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Science china chemistry 2009年第11期52卷 1825-1834页

作者： HUANG Kun1,CHEN Jing1,ZHANG ChengFeng1,2,LI ZhiHong3,PAN QingHua1,SUN Yan1,LIU ShaoXuan1,LIU XueXin2,LI WeiHong1,YANG ZhanLan1,WENG ShiFu1,HU TianDou3,XU YiZhuang1 & WU JinGuang1 1 College of chemistry and Molecular Engineering,Peking University,beijing 100871,china 2 institute of chemistry,chinese academy of sciences,beijing 100190,china 3 institute of High Energy Physics,chinese academy of sciences,beijing 100049,china 1. College of chemistry and Molecular Engineering Peking University Beijing 100871 China 2. institute of chemistry Chinese Academy of Sciences Beijing 100190 China 3. institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

In this paper,we have investigated the formation of the third-phase in tertiary amine(N235)-PtCl62--HCl system and the microscopic phase structural evolution of platinum-loaded organic phases before and after the occurrence of the *** third-phase is characterized by various spectroscopic techniques,and the small angle X-ray scattering(SAXS) experiments demonstrate the appearance of nano-aggregates,i.e.,water-in-oil reversed micelles,in the third *** experimental results indicate that(1) formation of the third phase is related to the aggregation behaviors of nano-reversed micelles in which a super-concentrated hydrochloric acid formed with the H+ to H2O molar ratio being much higher than that of the conventional 37 wt% saturated hydrochloric acid.(2) The occurrence of the super-concentrated HCl results in a great amount of H+ and Cl-ions enriched and confined within the nano-water pools of W/O reversed micelles in third ***,the coordination behaviors of platinum complex ions in that super-concentrated hydrochloric acid are very different from their corresponding behaviors in bulk aqueous *** is possible that H+ ions participate in the formation of such complexes as HmPtCl6z+ in the super-concentrated hydrochloric acid.(3) The relative contents of various HmPtCl6z+ complexes are different corresponding to the H+ ion concentrations in confined nanowater *** association ability of the acidified tertiary amine N235 molecules(R3NH+) with various HmPtCl6z+ complexes plays an important role in affecting the platinum extraction behaviors.

关键词： solvent extraction third phase super-concentrated hydrochloric acid tertiary amine platinum

Study of the effect of atorvastatin on the interaction between ICAM-1 and CD11b by live-cell single-molecule force spectroscopy

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Science china chemistry 2010年第4期53卷 752-758页

作者： LI Yi1, SHI XiaoLi2, LIU HuiLiang1, YI ShaoQiong3, ZHANG XueJie2 & FANG XiaoHong2 1Department of Cardiology, the General Hospital of chinese People’s Armed Police Forces, beijing 100039, china 2beijing National Laboratory for Molecular sciences institute of chemistry, chinese academy of sciences, beijing 100190, china 3State Key Laboratory of Pathogen and Biosecurity beijing institute of Microbiology and Epidemiology, beijing 100071, china 1. Department of Cardiology the General Hospital of Chinese People’s Armed Police Forces Beijing 100039 China2. Beijing National Laboratory for Molecular Sciences Chinese Academy of Sciences Beijing 100190 China4. Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China3. State Key Laboratory of Pathogen and Biosecurity Beijing 100071 China5. Beijing Institute of Microbiology and Epidemiology Beijing 100071 China

The interaction between the cell adhesion molecule CD11b and its ligand ICAM-1 plays an important role in inflammatory responses in the disease of atherosclerosis. Atorvastatin is a commonly prescribed statin drug which has been considered as one of the most potent therapeutic agents for atherosclerosis due to its lipid-lowering effect. Recently, there is a growing body of evidence that atorvastatin has anti-inflammatory effect. We have applied the advanced method of live-cell single-molecule force spectroscopy to investigate the effect of atorvastatin on adhesion force between ICAM-1 and CD11b. Our result showed that single-molecule binding force of ICAM-1 and CD11b detected by AFM in the living cells was about 40 pN, and atorvastatin did not affect this force by blocking ICAM-1 or CD11b. This was different from the ICAM-1 monoclonal antibody, which could directly reduce the binding force of ICAM-1 and CD11b. Flow cytometry results revealed that atorvastatin pretreatment decreased the ICAM-1 expression in TNF-α activated HUVECs, which may contribute to its anti-inflammatory effect. The study provides a new approach to study anti-inflammatory mechanism for clinic drugs.

关键词： atherosclerosis atorvastatin atomic force microscopy single-molecule force spectroscopy protein-protein interaction