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241.
Dr. Christopher D. Fage Dr. Thomas Lathouwers Michiel Vanmeert Dr. Ling-Jie Gao Dr. Kristof Vrancken Eveline-Marie Lammens Angus N. M. Weir Ruben Degroote Prof. Harry Cuppens Dr. Simone Kosol Prof. Thomas J. Simpson Prof. Matthew P. Crump Prof. Christine L. Willis Prof. Piet Herdewijn Prof. Eveline Lescrinier Prof. Rob Lavigne Prof. Jozef Anné Dr. Joleen Masschelein 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10636-10643
The enoyl-acyl carrier protein reductase enzyme FabI is essential for fatty acid biosynthesis in Staphylococcus aureus and represents a promising target for the development of novel, urgently needed anti-staphylococcal agents. Here, we elucidate the mode of action of the kalimantacin antibiotics, a novel class of FabI inhibitors with clinically-relevant activity against multidrug-resistant S. aureus. By combining X-ray crystallography with molecular dynamics simulations, in vitro kinetic studies and chemical derivatization experiments, we characterize the interaction between the antibiotics and their target, and we demonstrate that the kalimantacins bind in a unique conformation that differs significantly from the binding mode of other known FabI inhibitors. We also investigate mechanisms of acquired resistance in S. aureus and identify key residues in FabI that stabilize the binding of the antibiotics. Our findings provide intriguing insights into the mode of action of a novel class of FabI inhibitors that will inspire future anti-staphylococcal drug development. 相似文献
242.
Suresh K. Vasa Himanshu Singh Kristof Grohe Rasmus Linser 《Angewandte Chemie (International ed. in English)》2019,58(17):5758-5762
Solid‐state NMR spectroscopy has recently enabled structural biology with small amounts of non‐deuterated proteins, largely alleviating the classical sample production demands. Still, despite the benefits for sample preparation, successful and comprehensive characterization of complex spin systems in the few cases of higher‐molecular‐weight proteins has thus far relied on traditional 13C‐detected methodology or sample deuteration. Herein we show for a 29 kDa carbonic anhydrase:acetazolamide complex that different aspects of solid‐state NMR assessment of a complex spin system can be successfully accessed using a non‐deuterated, 500 μg sample in combination with adequate spectroscopic tools. The shown access to protein structure, protein dynamics, as well as biochemical parameters in amino acid sidechains, such as histidine protonation states, will be transferable to proteins that are not expressible in E. coli. 相似文献
243.
Dr. Atiruj Theppawong Tim Van de Walle Prof. Dr. Kristof Van Hecke Dr. Charlotte Grootaert Prof. Dr. John Van Camp Prof. Dr. Matthias D'hooghe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(54):12583-12600
Curcumin, the main component of turmeric (Curcuma longa) is known to display an interesting bioactivity profile, including pronounced anticancer properties. However, its low bioavailability, metabolic instability and nonspecific activity are concerns that have to be addressed before curcuminoids can be considered for therapeutic applications. Within that framework, intensive research has been carried out in the last decades to develop new curcumin derivatives, generally centered on standard modifications of the sp2 curcumin framework, with the aim to augment its bioavailability while maintaining or improving its anticancer properties. To find potential hit molecules by moving away from the classical flat curcumin framework, we investigated an unexplored modification to produce novel, out-of-plane 1,4-thiazepane-based curcuminoids and assessed the impact of this modification on the biological activity. In this way, 21 new, structurally diverse thiazepane scaffolds (4-aryl-1-(7-aryl-1,4-thiazepan-5-ylidene)but-3-en-2-ones) were synthesized, as well as some biologically interesting unexpected reaction products (such as 5-aryl-6-arylmethylene-3-ethoxycyclohex-2-en-1-ones and 4-acetyl-5-aryl-2-(3-arylacryloyl)-3-methylcyclohex-2-en-1-ones). All these analogues were subsequently tested on their antioxidant capacity, their cytotoxicity properties and their ROS (reactive oxygen species) production. Many compounds demonstrated interesting activities, with ten curcuminoids, whereof eight 1,4-thiazepane-based, showing better antiproliferative properties compared to their mother compounds, as well as an increased ROS production. This unprecedented 3D curcumin modification has thus delivered promising new hit compounds with good activity profiles eligible for further exploration. 相似文献
244.
Dimitrije Mara Dr. Flavia Artizzu Prof. Philippe F. Smet Dr. Anna M. Kaczmarek Prof. Kristof Van Hecke Prof. Rik Van Deun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(69):15944-15956
Two series of novel NIR-emissive complexes of Nd3+, Sm3+, Er3+ and Yb3+ with two different β-diketonate ligands (L1=4,4,4-trifluoro-1-phenyl-1,3-butadione and L2=4,4,4-trifluoro-1-(4-chlorophenyl)-1,3-butadione) are reported. The neutral triphenylphosphine oxide (tppo) ligand was used to replace coordinated water molecules in the first coordination sphere of the as-obtained [Ln(L1(2))3(H2O)2] complexes to afford water-free [Ln(L1(2))3(tppo)2] molecular species. Upon replacement of water molecules by tppo units, the NIR emission lifetimes of the Nd3+, Er3+and Sm3+complexes increase by about one order of magnitude up to values of ≈9, 8 and 113 ms while Yb3+ complexes reach intrinsic quantum yields as high as to ΦYb=6.5 %., which are remarkably high for fully hydrogenated complexes. Vibrational quenching by CH and OH oscillators has been quantitatively assessed by implementing the Förster's model of resonance energy transfer on the basis of experimental data. This study demonstrates that highly efficient NIR-emitting lanthanide complexes can be obtained with facile, cheap and accessible syntheses through a rational design. 相似文献
245.
Dr. Subhrajyoti Bhandary Marek Beliš Laurens Bourda Prof. Dr. Anna M. Kaczmarek Prof. Dr. Kristof Van Hecke 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304722
In the quest for essential energy solutions towards an ecological friendly future, the transformation of visible light/solar energy into mechanical motions in metal-free luminescent crystals offers a sustainable choice of smart materials for lightweight actuating, and all-organic electronic devices. Such green energy-triggered photodynamic motions with room temperature phosphorescence (RTP) emission in molecular crystals have not been reported yet. Here, we demonstrate three new stoichiometrically different Lewis acid-base molecular organoboron crystals (PS1, PS2, and PS3), which exhibit rapid photosalient effects (ballistic splitting, moving, and jumping) under both ultraviolet (UV) and visible light associated with quantitative single-crystal-to-single-crystal (SCSC) [2+2] cycloaddition of preorganized olefins. Furthermore, these systems respond to sunlight and mobile (white) flashlight with a complete SCSC transformation in a relatively slow fashion. Remarkably, all PS1, PS2, and PS3 crystals display visible light-promoted dynamic green RTP as their emission peaks promptly blue-shift, due to instantaneous photomechanical effects. Time-dependent structural mapping of intermediate photoproducts during fast SCSC [2+2] photoreaction, by X-ray photodiffraction, reveals a rationale for the origin of these photodynamic motions associated with rapid topochemical transformations. The reported light-driven behavior (mechanical motions, dynamic phosphorescence, and topochemical reactivity), is considered advantageous for the strategic design of stimuli-responsive multi-functional crystalline materials. 相似文献
246.
Two mononuclear cobalt(III) complexes, namely [LCo(tmtp)(H2O)]ClO4?MeOH ( 1 ) (tmtp = tri(m‐tolyl)phosphine) and [LCo(PPh3)(H2O)]PF6 ( 2 ), have been prepared from a polydentate ligand, N,N′‐bis(3‐methoxysalicylidehydene)cyclohexane‐1,2‐diamine ( H 2 L ). Standard analytical techniques such as elemental analysis and UV–visible and Fourier transform infrared spectroscopies were used to characterize both complexes. The solid‐state molecular structures of both complexes were confirmed from single‐crystal X‐ray diffraction analysis. Structural analyses show that the Co(III) ion occupies the centre of a distorted octahedron in a complex cation: [LCo(tmtp)(H2O)]+ and [LCo(PPh3)(H2O)]+ for 1 and 2 , respectively. Phenoxazinone synthase activities of both complexes were screened. Kinetic studies and other experimental observations reveal that the reaction follows rate saturation kinetics and proceeds through the formation of a catalyst (complex)–substrate adduct. The turnover number (Kcat) of complex 2 is 54.07 h?1, exhibiting better catalytic activity compared to 1 (Kcat = 45.11 h?1). 相似文献
247.
Mojtaba Amini Sajjad Bahadori Tekantappeh Bagher Eftekhari-Sis Parviz Gohari Derakhshandeh Kristof Van Hecke 《Journal of Coordination Chemistry》2017,70(9):1564-1572
A copper-containing polyoxovanadate nanocluster, [(C2H5)4N]4[V8Cu2O24]?2H2O (1), was synthesized through reaction between the Cu(NO3)2?3H2O and [(C2H5)4N]4VO3 in the molar ratio 1?:?4. Nanocluster 1 was characterized by IR, elemental analysis, XRD, SEM, TEM, and X-ray crystallography. The catalytic activity of 1 for the azide–alkyne cycloaddition of different terminal alkynes and organic azides generated in situ from sodium azide and different organic halides was tested. The protocol could afford the corresponding products in good to excellent yield at very low catalyst loadings (3.4 Mol%) under the optimized reaction conditions. 相似文献
248.