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201.
Uncovering the Stoichiometry of Pyrococcus furiosus RNase P,a Multi‐Subunit Catalytic Ribonucleoprotein Complex,by Surface‐Induced Dissociation and Ion Mobility Mass Spectrometry 下载免费PDF全文
Xin Ma Lien B. Lai Stella M. Lai Akiko Tanimoto Prof. Mark P. Foster Prof. Vicki H. Wysocki Prof. Venkat Gopalan 《Angewandte Chemie (International ed. in English)》2014,53(43):11483-11487
We demonstrate that surface‐induced dissociation (SID) coupled with ion mobility mass spectrometry (IM‐MS) is a powerful tool for determining the stoichiometry of a multi‐subunit ribonucleoprotein (RNP) complex assembled in a solution containing Mg2+. We investigated Pyrococcus furiosus (Pfu) RNase P, an archaeal RNP that catalyzes tRNA 5′ maturation. Previous step‐wise, Mg2+‐dependent reconstitutions of Pfu RNase P with its catalytic RNA subunit and two interacting protein cofactor pairs (RPP21?RPP29 and POP5?RPP30) revealed functional RNP intermediates en route to the RNase P enzyme, but provided no information on subunit stoichiometry. Our native MS studies with the proteins showed RPP21?RPP29 and (POP5?RPP30)2 complexes, but indicated a 1:1 composition for all subunits when either one or both protein complexes bind the cognate RNA. These results highlight the utility of SID and IM‐MS in resolving conformational heterogeneity and yielding insights on RNP assembly. 相似文献
202.
A Small‐Molecule FRET Reporter for the Real‐Time Visualization of Cell‐Surface Proteolytic Enzyme Functions 下载免费PDF全文
Jing Mu Dr. Fang Liu Muhammad Shafiq Rajab Meng Shi Shuang Li Chiching Goh Prof. Lei Lu Prof. Qing‐Hua Xu Prof. Bin Liu Dr. Lai Guan Ng Prof. Bengang Xing 《Angewandte Chemie (International ed. in English)》2014,53(52):14357-14362
Real‐time imaging of cell‐surface‐associated proteolytic enzymes is critical to better understand their performances in both physiological and pathological processes. However, most current approaches are limited by their complexity and poor membrane‐anchoring properties. Herein, we have designed and synthesized a unique small‐molecule fluorescent probe, which combines the principles of passive exogenous membrane insertion and Förster resonance energy transfer (FRET) to image cell‐surface‐localized furin‐like convertase activities. The membrane‐associated furin‐like enzymatic cleavage of the peptide probe leads to an increased fluorescence intensity which was mainly localized on the plasma membrane of the furin‐expressed cells. This small‐molecule fluorescent probe may serve as a unique and reliable reporter for real‐time visualization of endogenous cell‐surfaceassociated proteolytic furin‐like enzyme functions in live cells and tissues using one‐photon and two‐photon microscopy. 相似文献
203.
Lu Lai Ping Mei Xiao-Mei Wu Cong Hou Yan-Cheng Zheng Yi Liu 《Colloid and polymer science》2014,292(11):2821-2830
A series of anionic gemini surfactants have been synthesized. The surface properties and micellization process of as-prepared sulfonate gemini surfactants (SGS) and carboxylate gemini surfactant (CGS) have been studied by surface tension measurement and isothermal titration microcalorimetry. Meanwhile, the interaction of these five surfactants with polyacrylamide (PAM) was investigated using surface tension, steady-state fluorescence measurement, and isothermal titration microcalorimetry. The results show that the critical micelle concentrations (CMCs) of above-mentioned surfactants are more than 1 order of magnitude lower than those of corresponding single chain surfactants. Moreover, the enthalpy of micelle formation (ΔH mic) for the investigated gemini surfactants is negative. In the surfactant–PAM systems, the thermodynamic parameters of binding have also been determined. The conclusion may be drawn that the binding strength of SGS onto PAM is stronger than that of CGS, resulting from more compact structure of SGS aggregates. With increasing surfactant hydrophobicity, the values of ΔH agg become more exothermic and a ΔS agg decrease was observed. Therefore, the interaction between SGS and PAM is enthalpy-driven. 相似文献
204.
Wan-Feng Zhang Xiao-Ping Xia Takahashi Eiichi Li Li Qing Yang Yan-Qiang Zhang Ya-Nan Yang Ming-Liang Liu Chunkit Lai 《Surface and interface analysis : SIA》2020,52(5):224-233
Secondary ion mass spectrometry (SIMS) has a wide range of applications in Earth Science research, thanks to its high precision and sensitivity, and its capacity in direct insitu micromeasurement. The technique is operated in ultra-high vacuum (UHV) conditions, especially for the measurement of volatiles such as hydrogen, or the water content in nominally anhydrous minerals (NAMs). To minimize the water background and obtain accurate and precise water contents in NAMs (eg, olivine) critical parameters such as presputtering time, field aperture (FA), dynamic transfer on/off, and primary beam current intensity were investigated for a CAMECA IMS 1280-HR system. When the chamber vacuum reaches approximately 2 × 10−9 mbar, we set the DTOS OFF, raster size to 50 μm and primary beam current to 5 nA, and used 2000 μm FA and 170-second presputtering time. Consequently, an approximately 1.2 ppmw water background and 3.6 ppmw limit of detection (LOD) were yielded, from analyzing the San Carlos olivine. Meanwhile, the water content and homogeneity of a range of olivine minerals were characterized for potential use as reference materials for SIMS water content measurement. Olivine water content calibration curve was also established by comparing the Fourier transform infrared (FTIR) results with the SIMS-measured 16O1H−/16O− ratios. Accuracy and precision of water content measurement were estimated to be better than approximately 10% in this study. 相似文献
205.
Jiann-Jyh Huang Yu-Hsiang Lin Chun-Liang Lai Sheng-Chuan Yang Shu Fu Lin Ju-Ying Yang Hung-Jyun Huang Chiawei Liu Win-Yin Wei Shih-Hsien Chuang Chao-Cheng Chiang Ying-Shuen E. Lee Chu-Bin Liao Ching Yuh Chern 《中国化学会会志》2020,67(3):422-429
In this study, we reported the inhibition profiles of 4′-acylpyrrole–5-fluoroindolin-2-one 3 with a C-3′ side chain for VEGFR2, PDGFR-β, and FGFR-1 protein kinases. The pyrrole-fused cyclohexanone moiety provided 3 with the best potency to inhibit the three kinases, and the C-3′ side chains contributed to the different inhibition profiles of 3 . Compound 3b with a C-3′ 2-carboxylethyl side chain showed good potency for the three kinase (IC50: 25–260 nM), and compound 3g with a N,N-dialkyl-2-carbamoylethyl side chain was more active for VEGFR2 (IC50: 59 nM) and PDGFR-β (IC50: 16 nM) than FGFR-1 (IC50: 1.7 μM). The C-3′ 3-(dialkylamino)propyl side chain accomplished 3h – j as selective PDGFR-β inhibitors (IC50: 7.8–13 nM). Compound 3b was further investigated and found potent to inhibit VEGF- and FGF-dependent cell proliferation with moderate in vivo anticancer activity. Results from docking simulations revealed that the interactions of 3b with VEGFR2 and FGFR-1 which could account for the different inhibition profiles of 3 . 相似文献
206.
Dr. Yao Xiao Yan-Fang Zhu Dr. Wei Xiang Dr. Zhen-Guo Wu Yong-Chun Li Jing Lai Shi Li Dr. Enhui Wang Zu-Guang Yang Chun-Liu Xu Prof. Ben-He Zhong Prof. Xiao-Dong Guo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1507-1511
Demands for large-scale energy storage systems have driven the development of layered transition-metal oxide cathodes for room-temperature rechargeable sodium ion batteries (SIBs). Now, an abnormal layered-tunnel heterostructure Na0.44Co0.1Mn0.9O2 cathode material induced by chemical element substitution is reported. By virtue of beneficial synergistic effects, this layered-tunnel electrode shows outstanding electrochemical performance in sodium half-cell system and excellent compatibility with hard carbon anode in sodium full-cell system. The underlying formation process, charge compensation mechanism, phase transition, and sodium-ion storage electrochemistry are clearly articulated and confirmed through combined analyses of in situ high-energy X-ray diffraction and ex situ X-ray absorption spectroscopy as well as operando X-ray diffraction. This crystal structure engineering regulation strategy offers a future outlook into advanced cathode materials for SIBs. 相似文献
207.
Shuai Yang Kaijie Xu Qiuqin Lai Chen Zhao Hanhong Xu 《Journal of heterocyclic chemistry》2020,57(12):4304-4311
In searching for novel insecticidal leads, a series of N-pyridylpyrazolo-5-methyl amines and their derivatives were designed and synthesized. Among the 22 target compounds obtained, bioassays indicated that some of the target compounds exhibited good insecticidal activities against Plutella xylostella (P. xylostella) and Spodoptera frugiperda (S. frugiperda). In particular, compound 9j revealed the best insecticidal activity against P. xylostella, with a LC50 value of 22.11 mg/L, and compound 9q had the best insecticidal activity against S. frugiperda which with 73.99% of mortality rate at 100 mg/L. Structure-activity relationship (SAR) analysis showed that 4-CF3 at the position of R1 linked with N-pyridylpyrazole via amide bond could enhance the insecticidal activity of the target compounds. This study provides valuable clues for the further design and optimization of N-pyridylpyrazole derivatives. 相似文献
208.
Wuliang Feng Dr. Xiaoli Dong Xiang Zhang Zhengzhe Lai Panlong Li Prof. Dr. Congxiao Wang Prof. Dr. Yonggang Wang Prof. Dr. Yongyao Xia 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(13):5384-5387
Applying interlayers is the main strategy to address the large area specific resistance (ASR) of Li/garnet interface. However, studies on eliminating the Li2CO3 and LiOH interfacial lithiophobic contaminants are still insufficient. Here, thermal-decomposition vapor deposition (TVD) of a carbon modification layer on Li6.75La3Zr1.75Ta0.25O12 (LLZTO) provides a contaminant-free surface. Owing to the protection of the carbon layer, the air stability of LLZTO is also improved. Moreover, owing to the amorphous structure of the low graphitized carbon (LGC), instant lithiation is achieved, and the ASR of the Li/LLZTO interface is reduced to 9 Ω cm2. Lithium volatilization and Zr4+ reduction are also controllable during TVD. Compared with its high graphitized carbon counterpart (HGC), the LGC-modified Li/LLZTO interface displays a higher critical current density of 1.2 mA cm−2, as well as moderate Li plating and stripping, which provides enhanced polarization voltage stability. 相似文献
209.
Yao Xiao Yan‐Fang Zhu Wei Xiang Zhen‐Guo Wu Yong‐Chun Li Jing Lai Shi Li Enhui Wang Zu‐Guang Yang Chun‐Liu Xu Ben‐He Zhong Xiao‐Dong Guo 《Angewandte Chemie (International ed. in English)》2020,59(4):1491-1495
Demands for large‐scale energy storage systems have driven the development of layered transition‐metal oxide cathodes for room‐temperature rechargeable sodium ion batteries (SIBs). Now, an abnormal layered‐tunnel heterostructure Na0.44Co0.1Mn0.9O2 cathode material induced by chemical element substitution is reported. By virtue of beneficial synergistic effects, this layered‐tunnel electrode shows outstanding electrochemical performance in sodium half‐cell system and excellent compatibility with hard carbon anode in sodium full‐cell system. The underlying formation process, charge compensation mechanism, phase transition, and sodium‐ion storage electrochemistry are clearly articulated and confirmed through combined analyses of in situ high‐energy X‐ray diffraction and ex situ X‐ray absorption spectroscopy as well as operando X‐ray diffraction. This crystal structure engineering regulation strategy offers a future outlook into advanced cathode materials for SIBs. 相似文献
210.
Shan He Runchen Lai Qike Jiang Yaoyao Han Xiao Luo Yuyang Tian Xue Liu Kaifeng Wu 《Angewandte Chemie (International ed. in English)》2020,59(40):17726-17731
Triplet energy transfer from inorganic nanocrystals to molecular acceptors has attracted strong attention for high‐efficiency photon upconversion. Here we study this problem using CsPbBr3 and CdSe nanocrystals as triplet donors and carboxylated anthracene isomers as acceptors. We find that the position of the carboxyl anchoring group on the molecule dictates the donor‐acceptor coupling to be either through‐bond or through‐space, while the relative strength of the two coupling pathways is controlled by the wavefunction leakage of nanocrystals that can be quantitatively tuned by nanocrystal sizes or shell thicknesses. By simultaneously engineering molecular geometry and nanocrystal wavefunction, energy transfer and photon upconversion efficiencies of a nanocrystal/molecule system can be improved by orders of magnitude. 相似文献