2018 Volume 29 Issue 5

Biochemical reactions in metabolite-protein interaction
Wang Wen , Tekcham Dinesh Singh , Yan Min , Wang Zhichao , Qi Huan , Liu Xiaolong , Piao Hai-Long
2018, 29(5): 645-647  doi: 10.1016/j.cclet.2017.10.002
[Abstract](343) [FullText HTML] [PDF 698KB](0)
Active endogenous metabolites regulate the viability of cells. This process is controlled by a series of interactions between small metabolites and large proteins. Previously, several studies had reported that metabolite regulates the protein functions, such as diacylglycerol to protein kinase C, lactose regulation of the lac repressor, and HIF-1α stabilization by 2-hydroxyglutarate. However, decades old traditional biochemical methods are insufficient to systematically investigate the bio-molecular reactions for a highthroughput discovery. Here, we have reviewed an update on the recently developed chemical proteomics called activity-based protein profiling (ABPP). ABPP is able to identify proteins interacted either covalently or non-covalently with metabolites significantly. Thus, ABPP will facilitate the characterization of specific metabolite regulating proteins in human disease progression.
Biomarker-targeted fluorescent probes for breast cancer imaging
Yue Dongfang , Wang Meiling , Deng Fei , Yin Wenting , Zhao Haidong , Zhao Xiaoming , Xu Zhaochao
2018, 29(5): 648-656  doi: 10.1016/j.cclet.2018.01.046
[Abstract](2605) [FullText HTML] [PDF 1076KB](4)
Breast cancer has become a common tumor worldwide which seriously endangers people's health. Early diagnosis and treatment are particularly urgent in order to reduce the onset risk, mortality, and prolong the five-year survival rate. Therefore, we need a kind of diagnosis and treatment technology with high specificity, sensitivity and selectivity. In recent years, because of its unique properties in biological applications, fluorescence imaging has become an attractive research subject. Fluorescence imaging offers innovative ideas of targetable recognition of breast cancer cells, breast cancer imaging in vivo animal models, anticancer drugs delivery for guiding the mammary surgery via a noninvasive way with high sensitively and specifically. In this review, we summarized the recent advances of fluorescent probes for breast cancer imaging, which were classified according to different biomarkers the probes recognized. Moreover, we discussed the strengths, built-in problems as well as the challenges about the fluorescent probe as a unique potential method for the better application in breast cancer diagnosis and treatment.
Rapid development in two-dimensional layered perovskite materials and their application in solar cells
Ahmad Sajjad , Guo Xin
2018, 29(5): 657-663  doi: 10.1016/j.cclet.2017.08.057
[Abstract](1531) [FullText HTML] [PDF 1121KB](3)
Two-dimensional (2D) layered organic-inorganic hybrid perovskite (2D PVK) materials have been recently developed as a novel candidate for photovoltaic application with high stability and a maximum power conversion efficiency of 12.5%. This article summarized these newly emerging 2D PVK materials and their uses in solar cells. The structural, physical, and chemical properties as well as the classification of 2D PVK materials are discussed. The photovoltaic performance parameters of various 2D perovskite solar cells (2D PSCs) are summarized and their device stability is compared with conventional 3D perovskite solar cells (3D PSCs). It has been concluded that 2D PVKs show greater stability upon humidity, heat stress, and light intensity as compared to 3D analogues and act as a class of promising materials for application in solar cells.
Applications of low temperature calorimetry in material research
Liu Xin , Luo Jipeng , Yin Nan , Tan Zhi-Cheng , Shi Quan
2018, 29(5): 664-670  doi: 10.1016/j.cclet.2017.10.021
[Abstract](321) [FullText HTML] [PDF 804KB](0)
Low temperature calorimetry is an experimental method of heat capacity measurements, and heat capacity is one of the most important and fundamental thermodynamic properties of substances. The heat capacity can provide an average evaluation of the thermal property of a sample since it is a bulk property of substances. In the other hand, the condensed states of substances could be mainly controlled by the molecular motions, intermolecular interactions, and interplay among molecular structures. The physical property reflected in a material may be closely related to the energy changes in these three factors, which can be directly observed in a heat capacity curve. Therefore, low temperature calorimetry has been used not only to obtain heat capacity, entropy, enthalpy and Gibbs free energy, but also to investigate and understand lattice vibrations, metals, superconductivity, electronic and nuclear magnetism, dilute magnetic systems and structural transitions. In this review, we have presented the concept of low temperature calorimetry and its applications in the related field of material researches, such as nano-materials, magnetic materials, ferroelectric materials, phase change materials and other materials.
Species, engineering and characterizations of defects in TiO2-based photocatalyst
Dong Beibei , Liu Taifeng , Li Can , Zhang Fuxiang
2018, 29(5): 671-680  doi: 10.1016/j.cclet.2017.12.002
[Abstract](2502) [FullText HTML] [PDF 1166KB](4)
Light absorption, charge separation and surface reaction are considered as the main processes of photocatalysis on one semiconductor, and all of them are demonstrated to be related to the defect states of photocatalysts. This paper will choose TiO2 as model photocatalyst to introduce some basic concepts and strategies related to defects and methods developed to characterize defects in the past decades. Meanwhile, such strategies as hydrogenation and metal/nonmetal doping into TiO2 will be introduced to extend utilization of solar spectrum and/or to provide active sites. On the contrary, the unfavorable effect of defects such as acting as recombination centers of photogenerated carriers will also be introduced. Some typical methods to characterize the properties of defects are summarized, which contain electron paramagnetic resonance (EPR), photoluminescence technique (PL), positron annihilation spectroscopy (PAS), and so on. We do hope that this review will make a revealing effect on understanding to the functions of defects as well as construction of efficient photocatalytic systems in the future.
Advances in engineering methylotrophic yeast for biosynthesis of valuable chemicals from methanol
Duan Xingpeng , Gao Jiaoqi , Zhou Yongjin J.
2018, 29(5): 681-686  doi: 10.1016/j.cclet.2017.11.015
[Abstract](1408) [FullText HTML] [PDF 759KB](0)
Methylotrophic yeasts and bacteria, which can use methanol as carbon and energy source, have been wildly used as microbial cell factories for biomanufacturing. Due to their robustness in industrial harsh conditions, methylotrophic yeasts such as Pichia pastoris have been explored as a cell factory for production of proteins and high-value chemicals. Methanol utilization pathway (MUT) is highly regulated for efficient methanol utilization, and the downstream pathways need extensively constructed and optimized toward target metabolite biosynthesis. Here, we present an overview of methanol metabolism and regulation in methylotrophic yeasts, among which we focus on the regulation of key genes involved in methanol metabolism. Besides, the recent progresses in construction and optimization of downstream biosynthetic pathways for production of high value chemicals, such as polyketides, fatty acids and isoprenoids, are further summarized. Finally, we discuss the current challenges and feasible strategies toward constructing efficient methylotrophic cell factories may promote wide applications in the future.
Non-metallic gold nanoclusters for oxygen activation and aerobic oxidation
Zhang Guomei , Wang Ruru , Li Gao
2018, 29(5): 687-693  doi: 10.1016/j.cclet.2018.01.043
[Abstract](315) [FullText HTML] [PDF 980KB](1)
In recent decade, Au nanoclusters of atomic precision (AunLm, where L=organic ligand:thiolate and phosphine) have been shown as a new promising nanogold catalyst. The well-defined AunLm catalysts possess unique electronic properties and frameworks, providing an excellent opportunity to correlate the intrinsic catalytic behavior with the cluster's framework as well as to study the catalytic mechanisms over gold nanoclusters. In this review, we only demonstrate the important roles of the gold nanoclusters in the oxygen activation (e.g., 3O2 to 1O2) and their selective oxidations in the presence of oxygen (e.g., CO to CO2, sulfides to sulfoxides, alcohol to aldehyde, styrene to styrene epoxide, amines to imines, and glucose to gluconic acid). The size-specificity (Au25 (1.3 nm), Au38 (1.5 nm), Au144 (1.9 nm), etc.), ligand engineering (e.g., aromatic vs aliphatic), and doping effects (e.g., copper, silver, palladium, and platinum) are discussed in details. Finally, the proposed reactions' mechanism and the relationships of clusters' structure and activity at the atomic level also are presented.
Elucidating the various multi-phosphorylation statuses of protein functional regions by 193-nm ultraviolet photodissociation
Liu Zheyi , Jiang You , Xiao Chunlei , Xiong Xingchuang , Wang Tao , Li Jinan , Wang Fangjun , Fang Xiang , Yang Xueming
2018, 29(5): 694-698  doi: 10.1016/j.cclet.2017.10.020
[Abstract](792) [FullText HTML] [PDF 892KB](0)
Ultraviolet photodissociation is a high-energy fast excitation method in mass spectrometry and has been successfully applied for the elucidation of sequences and structures of biomolecules. However, its ability to distinguish the phosphorylation sites isomers of multi-phosphopeptides has been not systematically investigated until now. A 193-nm ultraviolet laser dissociation mass spectrometry system was established in this study and applied to elucidate the complex multi-phosphorylation statuses mimicking the functional regions of Sic1, Gli3 and Tau. The numbers of matched fragment ions and phosphorylation site-determining ions were improved on average 123% and 104%, respectively, by utilizing the ultraviolet photodissociation strategy, comparing to the typically utilized collision induced dissociation strategy. Finally, 94% phosphorylation sites within various statuses were unambiguously elucidated.
Carrier dynamics in CsPbI3 perovskite microcrystals synthesized in solution phase
Hu Jinwen , Zhao Chunyi , He Sheng , Tian Wenming , Hao Ce , Jin Shengye
2018, 29(5): 699-702  doi: 10.1016/j.cclet.2017.10.005
[Abstract](757) [FullText HTML] [PDF 859KB](2)
All-inorganic cesium lead halide perovskites (CsPbX3, X=Cl-, Br-, I-) could provide comparable optoelectronic properties as a promising class of materials for photovoltaic cell (PV), photodetector and light-emitting diode (LED) with enhanced thermal and moisture stabilities compared to organicinorganic lead halide species. However, fabrication of CsPbI3 perovskite via facile solution process has been difficult due to instability of CsPbI3 in the perovskite cubic phase in ambient air. Herein, we report the synthesis of CsPbI3 perovskite microcrystals by low-temperature, catalyst-free, solution-phase method. By applying the time-resolve spectroscopic technique, we determine the carrier diffusion coefficient of 0.6-1.2 cm2/s, the intrinsic carrier lifetimes of 200-1300 ns and diffusion length of 4-10 μm in different individual CsPbI3 perovskite microcrystals. Our results suggest the CsPbI3 perovskite microcrystals synthesized by solution process exhibit high quality feature and are suitable for applications in optoelectronic devices.
Aptamer based fluorescent probe for serum HER2-ECD detection: The clinical utility in breast cancer
Wang Meiling , Yue Dongfang , Qiao Qinglong , Miao Lu , Zhao Haidong , Xu Zhaochao
2018, 29(5): 703-706  doi: 10.1016/j.cclet.2018.03.025
[Abstract](720) [FullText HTML] [PDF 743KB](2)
The transmembrane protein HER2 is overexpressed in approximately 30% of breast cancer patients. HER2-positive breast cancers tend to spread more aggressively, which result in increased mortality in women. Nowadays, the real-time monitoring of HER2 status is important in clinical diagnosis and treatment for HER2-positive patients. Although IHC and FISH assay are standard methods to evaluate the tissue HER2 status, both approaches which required high quality tissue samples and are not suitable for monitoring the status of HER2 in real time. Since extracellular domain (ECD) of the HER2 receptor can be shed into the circulation, the serum test of HER2 ECD has been developed as an additional approach to probe HER2 overexpression. The serum test will be able to monitor the dynamic changes of HER2 status. In this paper, we detected serum HER2 ECD using Cy5-labeled HB5 aptamer as a result of its specific binding ability to HER2 ECD. This aptamer-based fluorescent probe is easily synthesized and modified and as sensitive as anti-HER2 antibodies. We believe that Cy5-HB5 may have application potentials in serum HER2 test for clinical utility of breast cancer, such as recurrence and metastases.
Radiofrequency field enhanced chemical ionization with vacuum ultraviolet lamp for miniature time-of-flight mass spectrometer
Zhou Lijuan , Jiang Jichun , Zhao Kun , Li Jinxu , Wu Chenxin , Li Haiyang , Tian Di , Hou Keyong
2018, 29(5): 707-710  doi: 10.1016/j.cclet.2017.11.021
[Abstract](650) [FullText HTML] [PDF 749KB](0)
It is difficult to rapidly and on-line detect trace volatile organic compounds for miniature mass spectrometry due to its limited sampling volume at slow pumping speed. In this paper, we developed a new radiofrequency field enhanced chemical ionization source (RF-ECI) with vacuum ultraviolet (VUV) lamp by coupling radiofrequency electric field and direct-current field together. The experiment results showed that the sensitivity of benzene, toluene, hydrogen sulfide and other compounds increased by 2-3 orders of magnitude under the introduction of RF-ECI comparing to traditional single photon ionization (SPI). At the same time, the reagent ion of O2+ realized the charge transfer reaction chemical ionization, and the RF-ECI effectively expanded the detection range of the VUV lamp based SPI. The VUV lamp has inherent advantages in the on-site analytical instrument for its small size and low power consumption, and the VUV lamp based RF-ECI miniature time-of-flight mass spectrometer (TOFMS) has a limit-ofdetection for H2S as low as 0.0571 mg/m3, and it is expected to be used widely in the field of on-site rapid analysis.
Tailoring thermal conductivity of bulk graphene oxide by tuning the oxidation degree
Meng Qing-Long , Liu Hengchang , Huang Zhiwei , Kong Shuang , Jiang Peng , Bao Xinhe
2018, 29(5): 711-715  doi: 10.1016/j.cclet.2017.10.028
[Abstract](340) [FullText HTML] [PDF 814KB](0)
Bulk graphene oxide (GO) shows great potential in a variety of applications, such as sensors, photodetectors, supercapacitors, lithium ion batteries and catalysts. However, its thermal conductivity, one of the most important and fundamental physical properties, is still less known. Herein, we have systematically investigated the thermal conductivity of bulk GOs and find that it can be tailored by tuning their oxidation degree during preparation process. Notably, the cross-plane thermal conductivity of bulk GO, in comparison with its precursor graphite, exhibits more than 100 times decrease at room temperature. The dependence of thermal conductivity of GO on oxidation degree is attributed to the chemical and structural changes by introducing oxygen atoms and oxygen-containing functional groups, which can lead to a significant enhancement in atomic-and nano-scale phonon scattering. Furthermore, we reveal that the thermal conductivity of bulk GOs exhibits evident anisotropic behavior. These results provide fundamental understanding and valuable information on thermal transport properties of bulk GOs for various practical applications.
A non-aqueous Li/organosulfur semi-solid flow battery
Wang Chenhui , Lai Qinzhi , Xu Pengcheng , Li Xianfeng , Zhang Huamin
2018, 29(5): 716-718  doi: 10.1016/j.cclet.2017.12.025
[Abstract](609) [FullText HTML] [PDF 791KB](0)
Non-aqueous flow batteries have attracted extensive attention due to the advantages of wide voltage window, high energy density and wide operating temperature and so on. Herein, tetramethylthiuram disulfide (TMTD) with high intrinsic capacity (223 mAh/g) and high solubility (~1 mol/L in chloroform) is investigated as the positive active material of the non-aqueous Li/disulfide semi-solid flow battery. The electrochemical activity and reversibility are investigated by cyclic voltammetry and linear scan voltammetry. This Li/TMTD battery with a high cell voltage of 3.36 V achieves coulombic efficiency of 99%, voltage efficiency of 73% and energy efficiency of 72% at the current density of 5 mA/cm2 with active material concentration of 0.1 mol/L. Moreover, the Li/TMTD battery can operate for 100 cycles without obvious efficiency decay, indicating good stability.
Cholesterol modulating the orientation of His17 in hepatitis C virus p7 (5a) viroporin-A molecular dynamic simulation study
Zhang Yuebin , Peng Xiangda , Ren Hong , Chu Huiying , Li Yan , Li Guohui
2018, 29(5): 719-723  doi: 10.1016/j.cclet.2017.09.053
[Abstract](272) [FullText HTML] [PDF 847KB](1)
Protein p7 of HCV is a 63 amino acid channel forming membrane protein essential for the progression of viral infection and the sensitivity of this channel to small-molecule inhibitors renders p7 a potential target for novel therapies against HCV infection. Previous biochemical experiments suggested that the His17 of p7 is a pore-lining residue and solvated-exposed to participate in channel gating. However, a recent NMR structural identification of the p7 hexamer in dodecylphosphocholine (DPC) micelles indicated that the His17 is embedded into the protein matrix. In this work, we performed molecular dynamic simulations to bridge the controversial observations. Our results illustrated that by incorporating the cholesterol into DOPC membranes to mimic an actual membrane-like composition, the orientation of His17 in the hexameric bundles spontaneously access to the central pore region, indicating a versatile property of the p7 viroporin conformation that could be voluntarily influenced by its surrounding environments.
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