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  1. Article: Effect of Nascent Peptide Steric Bulk on Elongation Kinetics in the Ribosome Exit Tunnel

    Po, Pengse / Andrey Kosolapov / Carol Deutsch / D. Miklos Szantai-Kis / E. James Petersson / Erin Delaney / Howard Gamper / Lee Speight / LiWei Tu / Ya-Ming Hou

    Journal of Molecular Biology. 2017 June 16, v. 429

    2017  

    Abstract: All proteins are synthesized by the ribosome, a macromolecular complex that accomplishes the life-sustaining tasks of faithfully decoding mRNA and catalyzing peptide bond formation at the peptidyl transferase center (PTC). The ribosome has evolved an ... ...

    Abstract All proteins are synthesized by the ribosome, a macromolecular complex that accomplishes the life-sustaining tasks of faithfully decoding mRNA and catalyzing peptide bond formation at the peptidyl transferase center (PTC). The ribosome has evolved an exit tunnel to host the elongating new peptide, protect it from proteolytic digestion, and guide its emergence. It is here that the nascent chain begins to fold. This folding process depends on the rate of translation at the PTC. We report here that besides PTC events, translation kinetics depend on steric constraints on nascent peptide side chains and that confined movements of cramped side chains within and through the tunnel fine-tune elongation rates.
    Keywords messenger RNA ; proteins ; proteolysis ; ribosomes
    Language English
    Dates of publication 2017-0616
    Size p. 1873-1888.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 80229-3
    ISSN 1089-8638 ; 0022-2836
    ISSN (online) 1089-8638
    ISSN 0022-2836
    DOI 10.1016/j.jmb.2017.04.019
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: Growth and characterization of textured well-faceted ZnO on planar Si(100), planar Si(111), and textured Si(100) substrates for solar cell applications

    Chin-Yi Tsai / Jyong-Di Lai / Shih-Wei Feng / Chien-Jung Huang / Chien-Hsun Chen / Fann-Wei Yang / Hsiang-Chen Wang / Li-Wei Tu

    Beilstein Journal of Nanotechnology, Vol 8, Iss 1, Pp 1939-

    2017  Volume 1945

    Abstract: In this work, textured, well-faceted ZnO materials grown on planar Si(100), planar Si(111), and textured Si(100) substrates by low-pressure chemical vapor deposition (LPCVD) were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), ... ...

    Abstract In this work, textured, well-faceted ZnO materials grown on planar Si(100), planar Si(111), and textured Si(100) substrates by low-pressure chemical vapor deposition (LPCVD) were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and cathode luminescence (CL) measurements. The results show that ZnO grown on planar Si(100), planar Si(111), and textured Si(100) substrates favor the growth of ZnO(110) ridge-like, ZnO(002) pyramid-like, and ZnO(101) pyramidal-tip structures, respectively. This could be attributed to the constraints of the lattice mismatch between the ZnO and Si unit cells. The average grain size of ZnO on the planar Si(100) substrate is slightly larger than that on the planar Si(111) substrate, while both of them are much larger than that on the textured Si(100) substrate. The average grain sizes (about 10–50 nm) of the ZnO grown on the different silicon substrates decreases with the increase of their strains. These results are shown to strongly correlate with the results from the SEM, AFM, and CL as well. The reflectance spectra of these three samples show that the antireflection function provided by theses samples mostly results from the nanometer-scaled texture of the ZnO films, while the micrometer-scaled texture of the Si substrate has a limited contribution. The results of this work provide important information for optimized growth of textured and well-faceted ZnO grown on wafer-based silicon solar cells and can be utilized for efficiency enhancement and optimization of device materials and structures, such as heterojunction with intrinsic thin layer (HIT) solar cells.
    Keywords atomic force microscopy ; cathode luminescence ; scanning electron microscopy ; silicon solar cells ; transparent conducting oxide ; X-ray diffraction ; ZnO ; Technology ; T ; Chemical technology ; TP1-1185 ; Science ; Q ; Physics ; QC1-999
    Subject code 530
    Language English
    Publishing date 2017-09-01T00:00:00Z
    Publisher Beilstein-Institut
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article: Catalytic hydroconversion of methanol-soluble portion from Xiaolongtan lignite over difunctional Ni/Z5A

    Li, Wei-Tu / Dong-Dong Zhang / Lu-Lu Guo / Shi-Chao Qi / Xiang-Xue Liu / Xian-Yong Wei / Zhan-Ku Li / Zhi-Min Zong

    Fuel processing technology. 2016 July, v. 148

    2016  

    Abstract: A highly active difunctional supported nickel catalyst Ni/Z5A was prepared by thermally decomposing nickel carbonyl onto zeolite 5A (Z5A). The catalytic hydroconversion (CHC) of methanol-soluble portion (MSP) from the methanolysis of Xiaolongtan lignite ... ...

    Abstract A highly active difunctional supported nickel catalyst Ni/Z5A was prepared by thermally decomposing nickel carbonyl onto zeolite 5A (Z5A). The catalytic hydroconversion (CHC) of methanol-soluble portion (MSP) from the methanolysis of Xiaolongtan lignite was investigated over Ni/Z5A at 200°C. Detailed molecular compositions of MSP and catalytically hydrogenated MSP (CHMSP) were characterized with a Fourier transform infrared spectrometer, gas chromatograph/mass spectrometer (GC/MS), and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (ESIFTICRMS). According to analysis with GC/MS, MSP is rich in aromatic ring- and/or heteroatom-containing compounds, while most of the GC/MS-detectable compounds in CHMSP are chain alkanes and cyclanes. The analysis with ESIFTICRMS shows that both the number and yields of oxygen- and/or nitrogen-containing species in MSP were dramatically reduced after the CHC. These facts indicate that Ni/Z5A effectively catalyzed heteroatom (especially O atom) removal from MSP and hydrogenation of MSP. Naphth-1-ol and oxybis(methylene)dibenzene (OBMDB) were used as lignite-related model compounds and their CHCs were investigated to further understand the catalysis of Ni/Z5A in the CHC of MSP. As a result, Ni/Z5A proved to have 2 functions, i.e., activating H2 to biatomic active hydrogen (BAAH) and heterolytically splitting H2 to H+ relatively free from Ni/Z5A and H− adsorbed on Ni/Z5A. Over Ni/Z5A, the CHCs of naphth-1-ol and OBMDB proceeded via BAAH and H+ transfer to mainly produce tetralin and decalin from naphth-1-ol and methylcyclohexane and toluene from OBMDB.
    Keywords alkanes ; catalysts ; catalytic activity ; Fourier transform infrared spectroscopy ; gas chromatography-mass spectrometry ; hydrogen ; hydrogenation ; lignite ; methanolysis ; models ; nickel ; protons ; spectrometers ; toluene ; zeolites
    Language English
    Dates of publication 2016-07
    Size p. 146-154.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1483666-x
    ISSN 0378-3820
    ISSN 0378-3820
    DOI 10.1016/j.fuproc.2016.02.036
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  4. Article: Characterization of Oxygen-Containing Species in Methanolysis Products of the Extraction Residue from Xianfeng Lignite with Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Liu, Fang-Jing / Li Peng / Li Wei-Tu / Li Zhan-Ku / Wang Yu-Gao / Wei Xian-Yong / Xie Rui-Lun / Zong Zhi-Min

    Energy & Fuels. 2014 Sept. 18, v. 28, no. 9

    2014  

    Abstract: Methanolysis of an extraction residue (ER) from Xianfeng lignite was carried out to obtain extracts 1–4 (E₁–E₄). The molecular compositions (MCs) of oxygen-containing species (OCSs) in E₁–E₄ were characterized using negative-ion ... ...

    Abstract Methanolysis of an extraction residue (ER) from Xianfeng lignite was carried out to obtain extracts 1–4 (E₁–E₄). The molecular compositions (MCs) of oxygen-containing species (OCSs) in E₁–E₄ were characterized using negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). In addition, solid-state ¹³C nuclear magnetic resonance and X-ray photoelectron spectrometry were used to analyze the carbon types and oxygen functional groups (OFGs) in the ER. The results show that the carbon skeleton structures in the ER are dominated by aliphatic (50.2%) and aromatic (44.9%) carbons. Methylene and methoxy carbons are the most abundant among the aliphatic carbons. Each aromatic cluster contains three rings on average with two substituent groups on each ring. The OFGs in the ER include hydroxy, ether, carbonyl, and carboxyl groups, among which the hydroxy group is the most abundant. The ESI FT-ICR MS analysis shows that the molecular mass distributions of E₁–E₄ range from 150 to 500 u. The Oₙ (n = 1–6) class species are the predominant OCSs in E₁–E₄, with 0–14 double bond equivalent (DBE) values and 9–34 carbon numbers (CNs). The most abundant Oₙ class species in E₁–E₄ are O₂, O₂, O₂–O₃, and O₃, respectively. The OCSs in E₄ contain low abundances of O₁ and O₂ class species but relatively high abundances of O₄–O₆ class species. In addition, the Oₙ class species in E₄ have narrower ranges of DBE values and CNs than those in E₁–E₃. A series of acidic species with different DBE values and CNs are assigned to alkanoic acids, alkanedioic acids, alkanetricarboxylic acids, alkylarenols, alkylarenediols, alkylarenetriols, and alkylarenoic acids. With high resolving power and mass accuracy, ESI FT-ICR MS is an effective technique for characterizing MC of the soluble portion from lignites, which will facilitate producing important chemicals from lignites.
    Keywords acids ; carbon ; ionization ; lignite ; mass spectrometry ; methanolysis ; molecular weight ; nuclear magnetic resonance spectroscopy ; oxygen ; ozone ; stable isotopes ; superoxide anion ; X-ray photoelectron spectroscopy
    Language English
    Dates of publication 2014-0918
    Size p. 5596-5605.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 1483539-3
    ISSN 1520-5029 ; 0887-0624
    ISSN (online) 1520-5029
    ISSN 0887-0624
    DOI 10.1021%2Fef501414g
    Database NAL-Catalogue (AGRICOLA)

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