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91.
Dr. Nan Chen Dr. Yuan Liu Yuanpei Li Prof. Dr. Chu Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16203-16209
Protein 4′-phosphopantetheinylation is an essential post-translational modification (PTM) in prokaryotes and eukaryotes. So far, only five protein substrates of this specific PTM have been discovered in mammalian cells. These proteins are known to perform important functions, including fatty acid biosynthesis and folate metabolism, as well as β-alanine activation. To explore existing and new substrates of 4′-phosphopantetheinylation in mammalian proteomes, we designed and synthesized a series of new pantetheine analogue probes, enabling effective metabolic labelling of 4′-phosphopantetheinylated proteins in HepG2 cells. In combination with a quantitative chemical proteomic platform, we enriched and identified all the currently known 4′-phosphopantetheinylated proteins with high confidence, and unambiguously determined their exact sites of modification. More encouragingly, we discovered, using targeted chemical proteomics, a potential 4′-phosphopantetheinylation site in the protein of mitochondrial dehydrogenase/reductase SDR family member 2 (DHRS2). 相似文献
92.
Chaonan Mu Wei Wang Jie Wang Chu Gong Dongmei Zhang Prof. Dr. Xinxing Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(48):21699-21703
While Type I and Type II photosensitizers are often carefully tailored to achieve their respective advantages in treating different cancers, the identifications of the Type I and II mechanisms as such, the key reaction intermediates, and the consequent oxidation products of the substrates have never been easy. Using our unique home-built field-induced droplet ionization mass spectrometry (FIDI-MS) method that selectively samples molecules at the air–water interface, here we show the facile determination of both Type I and II mechanisms of a poster-child photosensitizer, temoporfin, without the addition of any probes. The unstable doublet radical resulting from the hydrogen abstraction by the triplet temoporfin through the Type I mechanism is captured, manifesting the in situ advantage of FIDI-MS. We anticipate that the method developed in this study can be widely utilized in the future designs of novel photosensitizers and the screening of their photosensitization mechanisms. 相似文献
93.
Zhen Zhang Ying-Lin Gu Zheng-Yang Wang Huan-Nan Wang Yan Zhao Xue-Mei Chu Chun-Yan Zhang Mao-Cai Yan 《Journal of heterocyclic chemistry》2020,57(3):1165-1172
Novel indole amide derivatives C1-C10 were successfully synthesized and characterized by 1H NMR, 13C NMR, IR, MS, and elemental analysis, and their molecular formulas were C14H10N6O, C13H10N4O, C16H13N3O2, C19H14N2O2, C16H11N3OS, C15H13N3O, C12H9N5O, C16H10ClN3OS, C15H17N3O2, and C13H14N2O3, respectively. The primary biological activities of these compounds were evaluated in vitro by the DPPH assay, H2O2-induced oxidative stress injury assay, and cytotoxicity assay. The results indicated that compounds C1, C2, C4, C7, and C9 exhibited DPPH·scavenging ability, while C3, C4, C5, and C8 showed potent growth-inhibitory activities against various human tumor cells, including MDA-MB-231, Hela, A549, and HT29. Interestingly, compound C4 showed potent scavenging effects on the DPPH radical and possessed protective effect on H2O2-induced oxidative stress injury in human neuroblastoma SH-SY5Y cells at low concentrations; however, C4 exhibited significant toxicity against four human tumor cells at a higher concentration in all treatments, and the range of IC50 value was 7.91 to 13.35 μM. 相似文献
94.
ABSTRACTA short-focus microlens array using dielectric layer and inhomogeneous electric field over a homogeneous nematic liquid crystal (LC) layer is proposed. The top substrate has a planar indium tin oxide (ITO) electrode which is coated on the inner surface. The bottom substrate has strip ITO electrodes which are embedded in the dielectric layers. The inhomogeneous electric field generates a required gradient refractive index profile within the LC layer which, in turn, causes the focusing effect. Due to the thinner LC layer (15 μm), the spherical aberration should be negligible. Moreover, the fabrication process of the proposed microlens array can be easily carried out because of the layer-by-layer configuration. The simulation results show that the focal length of the LC microlens can be continuously tuned from infinity to 0.988 mm with the change of applied voltage. 相似文献
95.
Dr. Jan Schwabedissen Pia C. Trapp Dr. Hans-Georg Stammler Prof. Dr. Norbert W. Mitzel Zhuang Wu Xianxu Chu Prof. Dr. Xiaoqing Zeng 《ChemistryOpen》2020,9(9):913-920
Difluorothiophosphoryl isocyanate, F2P(S)NCO was characterized with UV/vis, NMR, IR (gas and Ar-matrix), and Raman (liquid) spectroscopy. Its molecular structure was also established by means of gas electron diffraction (GED) and single crystal X-ray diffraction (XRD) in the gas phase and solid state, respectively. The analysis of the spectroscopic data and molecular structures is complemented by extensive quantum-chemical calculations. Theoretically, the Cs symmetric syn-conformer is predicted to be the most stable conformation. Rotation about the P−N bond requires about 9 kJ mol−1 and the predicted existence of an anti-conformer is dependent on the quantum-chemical method used. This syn-orientation of the isocyanate group is the only one found in the gas phase and contained likewise in the crystal. The overall molecular structure is very similar in gas and solid, despite in the solid state the molecules arrange through intramolecular O⋅⋅⋅F contacts into layers, which are further interconnected by S⋅⋅⋅N, S⋅⋅⋅C and C⋅⋅⋅F contacts. Additionally, the photodecomposition of F2P(S)NCO to form CO, F2P(S)N, and F2PNCO is observed in the solid Ar-matrix. 相似文献
96.
Fan Song Fang Wang Lei Guo Xiaoliang Feng Yanyan Zhang Lingling Chu 《Angewandte Chemie (International ed. in English)》2020,59(1):177-181
A stereodivergent reductive coupling reaction between allylic carbonates and vinyl triflates to furnish both E‐ and Z‐configured 1,4‐dienes has been achieved by visible‐light‐induced photoredox/nickel dual catalysis. The mild reaction conditions allow good compatibility of both vinyl triflates and allylic carbonates. Notably, the stereoselectivity of this synergistic cross‐electrophile coupling can be tuned by an appropriate photocatalyst with a suitable triplet‐state energy, providing a practical and stereodivergent means to alkene synthesis. Preliminary mechanistic studies shed some light on the coupling step as well as the control of the stereoselectivity step. 相似文献
97.
Wen‐Chao Geng Dongmei Zhang Chu Gong Zhihao Li Kevin M. Barraza Jesse L. Beauchamp Dong‐Sheng Guo Xinxing Zhang 《Angewandte Chemie (International ed. in English)》2020,59(31):12684-12688
The oxidation of antioxidants by oxidizers imposes great challenges to both living organisms and the food industry. Here we show that the host–guest complexation of the carefully designed, positively charged, amphiphilic guanidinocalix[5]arene pentadodecyl ether (GC5A‐12C) and negatively charged oleic acid (OA), a well‐known cell membrane antioxidant, prevents the oxidation of the complex monolayers at the air–water interface from two potent oxidizers hydroxyl radicals (OH) and singlet delta oxygen (SDO). OH is generated from the gas phase and attacks from the top of the monolayer, while SDO is generated inside the monolayer and attacks amphiphiles from a lateral direction. Field‐induced droplet ionization mass spectrometry results have demonstrated that the host–guest complexation achieves steric shielding and prevents both types of oxidation as a result of the tight and “sleeved in” physical arrangement, rather than the chemical reactivity, of the complexes. 相似文献
98.
Chao Wang Min Hu Yueying Chu Xue Zhou Qiang Wang Guodong Qi Shenhui Li Jun Xu Feng Deng 《Angewandte Chemie (International ed. in English)》2020,59(18):7198-7202
The understanding of catalyst deactivation represents one of the major challenges for the methanol‐to‐hydrocarbon (MTH) reaction over acidic zeolites. Here we report the critical role of intermolecular π‐interactions in catalyst deactivation in the MTH reaction on zeolites H‐SSZ‐13 and H‐ZSM‐5. π‐interaction‐induced spatial proximities between cyclopentenyl cations and aromatics in the confined channels and/or cages of zeolites are revealed by two‐dimensional solid‐state NMR spectroscopy. The formation of naphtalene as a precursor to coke species is favored due to the reaction of aromatics with the nearby cyclopentenyl cations and correlates with both acid density and zeolite topology. 相似文献
99.
100.
XuanLin Meng Yang Li Chongchong Lu Man Zhao Ming Li ShaoLi Wang ChangBao Zhao Bao Lin LuYue Shang Zhaohui Chu Xinhua Ding 《Journal of separation science》2020,43(12):2311-2320
In a recent study, anthocyanins, which have a strong free radical‐scavenging activity, were examined for their potential to effectively prevent cancer. However, clinical trials are limited by the purity of the anthocyanin. Multiple methods are used to extract and purify anthocyanins. Based on previous work on Solanum nigrum, which is a widely distributed plant, in this study, DM130 macroporous resin, Sephadex LH20, and a C18 column were used to separate cis–trans anthocyanin isomers. These anthocyanins constitute the majority of total S. nigrum anthocyanins. The results showed that this “DM130‐LH20‐C18 system” can be used to obtain a cinnamic acid‐derived cis–trans anthocyanin, petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside, with a purity of 98.5%, for effective quantitation. In order to determine the antioxidant ability of the petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside cis–trans isomers, three ordinary methods were adopted. The maximum antioxidant ability of the cis–trans anthocyanin was dozens of times higher than that of vitamin C. 相似文献