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81.
82.
Two‐Step Protein Labeling by Using Lipoic Acid Ligase with Norbornene Substrates and Subsequent Inverse‐Electron Demand Diels–Alder Reaction 下载免费PDF全文
Marcel Best Anna Degen Mathis Baalmann Tobias T. Schmidt Dr. Richard Wombacher 《Chembiochem : a European journal of chemical biology》2015,16(8):1158-1162
Inverse‐electron‐demand Diels–Alder cycloaddition (DAinv) between strained alkenes and tetrazines is a highly bio‐orthogonal reaction that has been applied in the specific labeling of biomolecules. In this work we present a two‐step labeling protocol for the site‐specific labeling of proteins based on attachment of a highly stable norbornene derivative to a specific peptide sequence by using a mutant of the enzyme lipoic acid ligase A (LplAW37V), followed by the covalent attachment of tetrazine‐modified fluorophores to the norbornene moiety through the bio‐orthogonal DAinv . We investigated 15 different norbornene derivatives for their selective enzymatic attachment to a 13‐residue lipoic acid acceptor peptide (LAP) by using a standardized HPLC protocol. Finally, we used this two‐step labeling strategy to label proteins in cell lysates in a site‐specific manner and performed cell‐surface labeling on living cells. 相似文献
83.
Tagging Glycoproteins with Fluorescently Labeled GDP‐Fucoses by Using α1,3‐Fucosyltransferases 下载免费PDF全文
Dr. Katrin Seelhorst Katharina Pahnke Prof. Dr. Chris Meier Prof. Dr. Ulrich Hahn 《Chembiochem : a European journal of chemical biology》2015,16(13):1919-1924
Fucose‐containing glycans mediate a variety of biological processes, but there is little information on reaction processes and mechanisms mediated by fucosyltransferases. We recently reported on fluorescently labeled GDP‐β‐L ‐fucose‐ATTO 550, which enabled monitoring of α1,3‐fucosyltransferase activity. Here we present an extension to the previously described results, based on the synthesis of a fluorescein‐isothiocyanate (FITC)‐labeled and two carboxyfluorescein‐labeled (FAM‐labeled) NDP‐β‐L ‐fucose derivatives, and applied all four compounds in labeling of different glycoproteins with the aid of four different fucosyltransferases. The labeling processes were analyzed by in‐gel fluorescence and fluorescence polarization measurements. Comparison with the ATTO‐labeled sugar revealed that the FITC‐labeled fucose was the best of these substrates, and that the bacterial enzyme HP‐FucT tolerated the fluorescent substrates better than human fucosyltransferases. 相似文献
84.
In Vivo Incorporation of Azide Groups into DNA by Using Membrane‐Permeable Nucleotide Triesters 下载免费PDF全文
Dr. Masayuki Tera Dr. Stella M. K. Glasauer Prof. Dr. Nathan W. Luedtke 《Chembiochem : a European journal of chemical biology》2018,19(18):1939-1943
Metabolic incorporation of bioorthogonal functional groups into cellular nucleic acids can be impeded by insufficient phosphorylation of nucleosides. Previous studies found that 5azidomethyl‐2′‐deoxyuridine (AmdU) was incorporated into the DNA of HeLa cells expressing a low‐fidelity thymidine kinase, but not by wild‐type HeLa cells. Here we report that membrane‐permeable phosphotriester derivatives of AmdU can exhibit enhanced incorporation into the DNA of wild‐type cells and animals. AmdU monophosphate derivatives bearing either 5′‐bispivaloyloxymethyl (POM), 5′‐bis‐(4‐acetoxybenzyl) (AB), or “Protide” protective groups were used to mask the phosphate group of AmdU prior to its entry into cells. The POM derivative “POM‐AmdU” exhibited better chemical stability, greater metabolic incorporation efficiency, and lower toxicity than “AB‐AmdU”. Remarkably, the addition of POM‐AmdU to the water of zebrafish larvae enabled the biosynthesis of azide‐modified DNA throughout the body. 相似文献
85.
A heavy crude oil has been treated with deuterated alkylating reagents (CD3I and C2D5I) and directly analyzed without any prior fractionation and chromatographic separation by high-field Orbitrap Fourier Transform Mass Spectrometry (FTMS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) using electrospray ionization (ESI). The reaction of a polycyclic aromatic sulfur heterocycles (PASHs) dibenzothiophene (DBT), in the presence of silver tetrafluoroborate (AgBF4) with ethyl iodide (C2H5I) in anhydrous dichloroethane (DCE) was optimized as a sample reaction to study heavy crude oil mixtures, and the reaction yield was monitored and determined by proton nuclear magnetic resonance spectroscopy (1H-NMR). The obtained conditions were then applied to a mixture of standard aromatic CH-, N-, O- and S-containing compounds and then a heavy crude oil, and only sulfur-containing compounds were selectively alkylated. The deuterium labeled alkylating reagents, iodomethane-d3 (CD3I) and iodoethane-d5 (C2D5I), were employed to the alkylation of heavy crude oil to selectively differentiate the tagged sulfur species from the original crude oil. 相似文献
86.
Farshad Rostamabadi Author Vitae Mohammad Ghodsi Author Vitae 《Computers & Electrical Engineering》2010,36(5):895-901
We consider an incremental optimal label placement in a closed-2PM map containing points each attached with a label. Labels are assumed to be axis-parallel square-shaped and have to be pairwise disjoint with maximum possible length each attached to its corresponding point on one of its horizontal edges. Such a labeling is denoted as optimal labeling. Our goal is to efficiently generate a new optimal labeling for all points after each new point being inserted in the map. Inserting each point may require several labels to flip or all labels to shrink. We present an algorithm that generates each new optimal labeling in O(lgn+k) time where k is the number of required label flips, if there is no need to shrink the label lengths, or in O(n) time when we have to shrink the labels and flip some of them. The algorithm uses O(n) space in both cases. This is a new result on this problem. 相似文献
87.
楼芊 《有色冶金设计与研究》2010,31(1):22-24
结合相关标准对常用焊缝符号的组成、标注方式及在焊缝基本要素和辅助要素标注过程中经常出现的问题作简要阐述。 相似文献
88.
89.
根据网络系统中的连续定理和最大容量等概念,建立了求解最大流量问题的一种简捷算法。此方法改进了惯用的Ford—Fulkerson标记化方法,去掉其繁琐性,因而有更大的实用价值。 相似文献
90.
This paper proposes a new, efficient algorithm for extracting similar sections between two time sequence data sets. The algorithm,
called Relay Continuous Dynamic Programming (Relay CDP), realizes fast matching between arbitrary sections in the reference
pattern and the input pattern and enables the extraction of similar sections in a frame synchronous manner. In addition, Relay
CDP is extended to two types of applications that handle spoken documents. The first application is the extraction of repeated
utterances in a presentation or a news speech because repeated utterances are assumed to be important parts of the speech.
These repeated utterances can be regarded as labels for information retrieval. The second application is flexible spoken document
retrieval. A phonetic model is introduced to cope with the speech of different speakers. The new algorithm allows a user to
query by natural utterance and searches spoken documents for any partial matches to the query utterance. We present herein
a detailed explanation of Relay CDP and the experimental results for the extraction of similar sections and report results
for two applications using Relay CDP.
Yoshiaki Itoh has been an associate professor in the Faculty of Software and Information Science at Iwate Prefectural University, Iwate,
Japan, since 2001. He received the B.E. degree, M.E. degree, and Dr. Eng. from Tokyo University, Tokyo, in 1987, 1989, and
1999, respectively. From 1989 to 2001 he was a researcher and a staff member of Kawasaki Steel Corporation, Tokyo and Okayama.
From 1992 to 1994 he transferred as a researcher to Real World Computing Partnership, Tsukuba, Japan. Dr. Itoh's research
interests include spoken document processing without recognition, audio and video retrieval, and real-time human communication
systems. He is a member of ISCA, Acoustical Society of Japan, Institute of Electronics, Information and Communication Engineers,
Information Processing Society of Japan, and Japan Society of Artificial Intelligence.
Kazuyo Tanaka has been a professor at the University of Tsukuba, Tsukuba, Japan, since 2002. He received the B.E. degree from Yokohama
National University, Yokohama, Japan, in 1970, and the Dr. Eng. degree from Tohoku University, Sendai, Japan, in 1984. From
1971 to 2002 he was research officer of Electrotechnical Laboratory (ETL), Tsukuba, Japan, and the National Institute of Advanced
Science and Technology (AIST), Tsukuba, Japan, where he was working on speech analysis, synthesis, recognition, and understanding,
and also served as chief of the speech processing section. His current interests include digital signal processing, spoken
document processing, and human information processing. He is a member of IEEE, ISCA, Acoustical Society of Japan, Institute
of Electronics, Information and Communication Engineers, and Japan Society of Artificial Intelligence.
Shi-Wook Lee received the B.E. degree and M.E. degree from Yeungnam University, Korea and Ph.D. degree from the University of Tokyo in
1995, 1997, and 2001, respectively. Since 2001 he has been working in the Research Group of Speech and Auditory Signal Processing,
the National Institute of Advanced Science and Technology (AIST), Tsukuba, Japan, as a postdoctoral fellow. His research interests
include spoken document processing, speech recognition, and understanding. 相似文献