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排序方式: 共有656条查询结果,搜索用时 78 毫秒
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Dr. Jianing Xie Dr. Axel Pahl Dr. Adrian Krzyzanowski Anna Krupp Dr. Jie Liu Sandra Koska Beate Schölermann Dr. Ruirui Zhang Jana Bonowski Dr. Sonja Sievers Prof. Dr. Carsten Strohmann Dr. Slava Ziegler Dr. Michael Grigalunas Prof. Dr. Herbert Waldmann 《Angewandte Chemie (International ed. in English)》2023,62(48):e202310222
Monoterpene indole alkaloids (MIAs) are endowed with high structural and spatial complexity and characterized by diverse biological activities. Given this complexity-activity combination in MIAs, rapid and efficient access to chemical matter related to and with complexity similar to these alkaloids would be highly desirable, since such compound classes might display novel bioactivity. We describe the design and synthesis of a pseudo-natural product (pseudo-NP) collection obtained by the unprecedented combination of MIA fragments through complexity-generating transformations, resulting in arrangements not currently accessible by biosynthetic pathways. Cheminformatic analyses revealed that both the pseudo-NPs and the MIAs reside in a unique and common area of chemical space with high spatial complexity-density that is only sparsely populated by other natural products and drugs. Investigation of bioactivity guided by morphological profiling identified pseudo-NPs that inhibit DNA synthesis and modulate tubulin. These results demonstrate that the pseudo-NP collection occupies similar biologically relevant chemical space that Nature has endowed MIAs with. 相似文献
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Theresa Hune Dr. Salvatore Mamone Dr. Henning Schroeder Dr. Anil P. Jagtap Sonja Sternkopf Dr. Gabriele Stevanato Dr. Sergey Korchak Claudia Fokken Christoph A. Müller Andreas B. Schmidt Dr. Dorothea Becker Dr. Stefan Glöggler 《Chemphyschem》2023,24(2):e202200615
The metabolism of malignant cells differs significantly from that of healthy cells and thus, it is possible to perform metabolic imaging to reveal not only the exact location of a tumor, but also intratumoral areas of high metabolic activity. Herein, we demonstrate the feasibility of metabolic tumor imaging using signal-enhanced 1-13C-pyruvate-d3, which is rapidly enhanced via para-hydrogen, and thus, the signal is amplified by several orders of magnitudes in less than a minute. Using as a model, human melanoma xenografts injected with signal-enhanced 1-13C-pyruvate-d3, we show that the conversion of pyruvate into lactate can be monitored along with its kinetics, which could pave the way for rapidly detecting and monitoring changes in tumor metabolism. 相似文献
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Sonja Kracht Dr. Matthias Messerer Dr. Matthieu Lang Dr. Sonja Eckhardt Dr. Miriam Lauz Prof. Bernard Grobéty Prof. Katharina M. Fromm Prof. Bernd Giese 《Angewandte Chemie (International ed. in English)》2015,54(10):2912-2916
Some microorganisms perform anaerobic mineral respiration by reducing metal ions to metal nanoparticles, using peptide aggregates as medium for electron transfer (ET). Such a reaction type is investigated here with model peptides and silver as the metal. Surprisingly, Ag+ ions bound by peptides with histidine as the Ag+‐binding amino acid and tyrosine as photoinducible electron donor cannot be reduced to Ag nanoparticles (AgNPs) under ET conditions because the peptide prevents the aggregation of Ag atoms to form AgNPs. Only in the presence of chloride ions, which generate AgCl microcrystals in the peptide matrix, does the synthesis of AgNPs occur. The reaction starts with the formation of 100 nm Ag@AgCl/peptide nanocomposites which are cleaved into 15 nm AgNPs. This defined transformation from large nanoparticles into small ones is in contrast to the usually observed Ostwald ripening processes and can be followed in detail by studying time‐resolved UV/Vis spectra which exhibit an isosbestic point. 相似文献
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Kyoung-Soon Jang Roger R. Nani Anastasia Kalli Sergiy Levin Axel Müller Sonja Hess Sarah E. Reisman William M. ClemonsJr. 《Analytical and bioanalytical chemistry》2015,407(20):6181-6190
In Campylobacterales and related ε-proteobacteria with N-linked glycosylation (NLG) pathways, free oligosaccharides (fOS) are released into the periplasmic space from lipid-linked precursors by the bacterial oligosaccharyltransferase (PglB). This hydrolysis results in the same molecular structure as the oligosaccharide that is transferred to a protein to be glycosylated. This allowed for the general elucidation of the fOS-branched structures and monosaccharides from a number of species using standard enrichment and mass spectrometry methods. To aid characterization of fOS, hydrazide chemistry has often been used for chemical modification of the reducing part of oligosaccharides resulting in better selectivity and sensitivity in mass spectrometry; however, the removal of the unreacted reagents used for the modification often causes the loss of the sample. Here, we develop a more robust method for fOS purification and characterize glycostructures using complementary tandem mass spectrometry (MS/MS) analysis. A cationic cysteine hydrazide derivative was synthesized to selectively isolate fOS from periplasmic fractions of bacteria. The cysteine hydrazide nicotinamide (Cyhn) probe possesses both thiol and cationic moieties. The former enables reversible conjugation to a thiol-activated solid support, while the latter improves the ionization signal during MS analysis. This enrichment was validated on the well-studied Campylobacter jejuni by identifying fOS from the periplasmic extracts. Using complementary MS/MS analysis, we approximated data of a known structure of the fOS from Campylobacter concisus. This versatile enrichment technique allows for the exploration of a diversity of protein glycosylation pathways. 相似文献
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Queiroz Ana Luiza P. Kerins Brian M. Yadav Jayprakash Farag Fatma Faisal Waleed Crowley Mary Ellen Lawrence Simon E. Moynihan Humphrey A. Healy Anne-Marie Vucen Sonja Crean Abina M. 《Cellulose (London, England)》2021,28(14):8971-8985
Cellulose - Microcrystalline cellulose (MCC) is a semi-crystalline material with inherent variable crystallinity due to raw material source and variable manufacturing conditions. MCC crystallinity... 相似文献
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The vibrational spectroscopy of lithium dichloride anions microhydrated with one to three water molecules, [LiCl2(H2O)1–3]−, is studied in the OH stretching region (3800–2800 cm−1) using isomer-specific IR/IR double-resonance population labelling experiments. The spectroscopic fingerprints of individual isomers can only be unambiguously assigned after anharmonic effects are considered, but then yield molecular level insight into the onset of salt dissolution in these gas phase model systems. Based on the extent of the observed frequency shifts ΔνOH of the hydrogen-bonded OH stretching oscillators solvent-shared ion pair motifs (<3200 cm−1) can be distinguished from intact-core structures (>3200 cm−1). The characteristic fingerprint of a water molecule trapped directly in-between two ions of opposite charge provides an alternative route to evaluate the extent of ion pairing in aqueous electrolyte solutions. 相似文献