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JPC – Journal of Planar Chromatography – Modern TLC - Prostaglandins are biological lipid mediators that control a variety of physiological and pathophysiological processes. They... 相似文献
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Swapping Interface Contacts in the Homodimeric tRNA‐Guanine Transglycosylase: An Option for Functional Regulation
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Dr. Frederik Rainer Ehrmann Jorna Kalim Dr. Toni Pfaffeneder Dr. Bruno Bernet Dr. Christoph Hohn Dr. Elisabeth Schäfer Dr. Thomas Botzanowski Dr. Sarah Cianférani Prof. Dr. Andreas Heine Prof. Dr. Klaus Reuter Prof. Dr. François Diederich Prof. Dr. Gerhard Klebe 《Angewandte Chemie (International ed. in English)》2018,57(32):10085-10090
The enzyme tRNA‐guanine transglycosylase, a target to fight Shigellosis, recognizes tRNA only as a homodimer and performs full nucleobase exchange at the wobble position. Active‐site inhibitors block the enzyme function by competitively replacing tRNA. In solution, the wild‐type homodimer dissociates only marginally, whereas mutated variants show substantial monomerization in solution. Surprisingly, one inhibitor transforms the protein into a twisted state, whereby one monomer unit rotates by approximately 130°. In this altered geometry, the enzyme is no longer capable of binding and processing tRNA. Three sugar‐type inhibitors have been designed and synthesized, which bind to the protein in either the functionally competent or twisted inactive state. They crystallize with the enzyme side‐by‐side under identical conditions from the same crystallization well. Possibly, the twisted inactive form corresponds to a resting state of the enzyme, important for its functional regulation. 相似文献
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F. F. Tisdall A. R. Ling J. H. Bushill A. C. Alport K. Ohmi L. Condorelli J. S. Sharpe K. Myrbäck R. V. Stanford A. H. M. Wheatley A. Mirkin S. J. Druskin W. Mestrezat R. Fabre Détrois K. Blühdorn Grete Genck A. Hirth A. Klotz G. de Toni P. Ronaund H. Kleinmann Leonia Kriss F. Lebermann B. Kramer Shun-Ichi Yoshimatsu C. H. Fiske G. Litarczek D. Olmer L. Payan J. Berthier I. Gittleman 《Analytical and bioanalytical chemistry》1928,74(3-4):151-160
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Numerical Algorithms - We construct approximate Fekete point sets for kernel-based interpolation by maximising the determinant of a kernel Gram matrix obtained via truncation of an orthonormal... 相似文献
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Cells continuously produce reactive oxidative species that can modify all cellular components. In proteins, for example, cysteine, methionine, tryptophan (Trp), and tyrosine residues are particularly prone to oxidation. Here, we report two new approaches to distinguish two isomeric oxidation products of Trp residues, i.e. 5-hydroxytryptophan (5-HTP) and oxindolylalanine (Oia) residues, in peptides. First, 2-nitrobenzenesulfenyl chloride, known to derivatize Trp residues in position 2 of the indole ring, was used to label 5-HTP residues. The mass shift of 152.98 m/z units allowed identifying 5-HTP- besides Trp-containing peptides by mass spectrometry, whereas Oia residues were not labeled. Second, fragmentation of the Oia- and 5-HTP-derived immonium ions at m/z 175.08 produced ions characteristic for each residue that allowed their identification even in the presence of y(1) ions at m/z 175.12 derived from peptides with C-terminal arginine residues. The pseudo MS(3) spectra acquired on a quadrupole time-of-flight hybrid mass spectrometer displayed two signals at m/z 130.05 and m/z 132.05 characteristic for Oia-containing peptides and a group of six signals (m/z 103.04, 120.04, 130.04, 133.03, 146.04, and 148.04) for 5-HTP-cointaining peptides. In both cases, the relative signal intensities appeared to be independent of the sequence providing a specific fingerprint of each oxidative modification. 相似文献
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Toni Mäkinen 《Applied Acoustics》2010,71(10):902-913
Shooter localization and estimation of bullet trajectory, caliber and speed have become essential tasks for example in peacekeeping and police assignments. A novel approach for such estimation and localization is presented in this paper, as a numerical estimation method is applied to the problem. Both simulated and recorded gunshot data are considered, as a known bullet shock wave model and detected firing sounds are utilized in creating a likelihood function corresponding to different bullet states. For this, a state-space model of the underlying dynamic system is developed, and a well-known optimization algorithm is used to find the global maximum of the evaluated function. Two different criteria are used to measure the likelihood values, namely the Generalized Cross Correlation (GCC) and the Mean-Squared Error (MSE). The achieved localization and estimation results are accurate and applicable when considering the usability of the method against hostile snipers. The shooter position and bullet state estimation errors vary between 2% and 10%, depending on the estimated parameter at stake. 相似文献