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491.
Inga Shybeka Alexander Aster Dr. Yangyang Cheng Dr. Naomi Sakai Prof. Antonio Frontera Prof. Eric Vauthey Prof. Stefan Matile 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(62):14059-14063
Naphthalenediimides (NDIs) are privileged scaffolds par excellence, of use in functional systems from catalysts to ion channels, photosystems, sensors, ordered matter in all forms, tubes, knots, stacks, sheets, vesicles, and colored over the full visible range. Despite this extensively explored chemical space, there is still room to discover core-substituted NDIs with fundamentally new properties: NDIs with cyclic trisulfides (i.e., trisulfanes) in their core absorb at 668 nm, emit at 801 nm, and contract into disulfides (i.e., dithietes) upon irradiation at <475 nm. Intramolecular 1,5-chalcogen bonds account for record redshifts with trisulfides, ring-tension mediated chalcogen-bond-mediated cleavage for blueshifts to 492 nm upon ring contraction. Cyclic oligochalcogenides (COCs) in the NDI core open faster than strained dithiolanes as in asparagusic acid and are much better retained on thiol exchange affinity columns. This makes COC-NDIs attractive not only within the existing multifunctionality, particularly artificial photosystems, but also for thiol-mediated cellular uptake. 相似文献
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Inga R. Grin Grigory V. Mechetin Rustem D. Kasymov Evgeniia A. Diatlova Anna V. Yudkina Sergei N. Shchelkunov Irina P. Gileva Alexandra A. Denisova Grigoriy A. Stepanov Ghermes G. Chilov Dmitry O. Zharkov 《Molecules (Basel, Switzerland)》2021,26(21)
Uracil–DNA glycosylases are enzymes that excise uracil bases appearing in DNA as a result of cytosine deamination or accidental dUMP incorporation from the dUTP pool. The activity of Family 1 uracil–DNA glycosylase (UNG) activity limits the efficiency of antimetabolite drugs and is essential for virulence in some bacterial and viral infections. Thus, UNG is regarded as a promising target for antitumor, antiviral, antibacterial, and antiprotozoal drugs. Most UNG inhibitors presently developed are based on the uracil base linked to various substituents, yet new pharmacophores are wanted to target a wide range of UNGs. We have conducted virtual screening of a 1,027,767-ligand library and biochemically screened the best hits for the inhibitory activity against human and vaccinia virus UNG enzymes. Although even the best inhibitors had IC50 ≥ 100 μM, they were highly enriched in a common fragment, tetrahydro-2,4,6-trioxopyrimidinylidene (PyO3). In silico, PyO3 preferably docked into the enzyme’s active site, and in kinetic experiments, the inhibition was better consistent with the competitive mechanism. The toxicity of two best inhibitors for human cells was independent of the presence of methotrexate, which is consistent with the hypothesis that dUMP in genomic DNA is less toxic for the cell than strand breaks arising from the massive removal of uracil. We conclude that PyO3 may be a novel pharmacophore with the potential for development into UNG-targeting agents. 相似文献
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Luc Ubaghs Nicole Fricke Helmut Keul Hartwig Hcker 《Macromolecular rapid communications》2004,25(3):517-521
Communication: Phenoxycarbonyloxymethyl ethylene carbonate 4 was synthesized from glycerol carbonate and phenyl chloroformate. Polyurethanes with pendant hydroxyl groups were obtained from polycondensation reactions of this AA* monomer with diamines. These polymers contain primary as well as secondary hydroxyl groups. The obtained polyurethanes are amorphous materials. The glass transition temperature decreases with increasing number of methylene groups between the urethane groups.
497.
Back Cover: Compact,Polyvalent Mannose Quantum Dots as Sensitive,Ratiometric FRET Probes for Multivalent Protein–Ligand Interactions (Angew. Chem. Int. Ed. 15/2016) 下载免费PDF全文
498.
A novel, efficient, and powerful methyl mercaptoacetate triggered benzannulation reaction is described. The precursors are heterocyclic, aromatic or acyclic compounds bearing a carbonyl group at ortho position to an internal alkyne. The methodology does not require transition-metal catalysts and moreover it is general for the preparation of wide range of benzo-annelated heterocycles, naphthalenes and benzenes. 相似文献
499.
Dr. Kirsten Schwing Dr. Holger Fricke Dr. Kristina Bartl Dr. Jolanta Polkowska Prof. Dr. Thomas Schrader Prof. Dr. Markus Gerhards 《Chemphyschem》2012,13(6):1576-1582
The functionality of bioactive molecules sensitively depends on their structure. For the investigation of intrinsic structural properties, molecular beam experiments combined with laser spectroscopy have proven to be a suitable tool. Herein we present an analysis of the two isolated tripeptide model systems Ac‐Phe‐Tyr(Me)‐NHMe and Boc‐Phe‐Tyr(Me)‐NHMe. For this purpose, mass‐selective combined IR/UV spectroscopy is applied to both substances in a molecular beam experiment. The comparison of the experimental data with DFT calculations, including different functionals as well as dispersion corrections, allows an assignment of both tripeptide models to β‐turns formed independently from the protection groups and supported by the interaction of the two aromatic chromophores. 相似文献
500.
Bacterial T3SS needles formed by the protein MxiH are studied using DNP‐enhanced ssNMR spectroscopy at 14.1 T (600 MHz). This technique provides spectra of good resolution, allowing us to draw conclusions about the protein dynamics. With the obtained signal enhancement, samples of limited quantity now get within reach of ssNMR studies. 相似文献