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排序方式: 共有113条查询结果,搜索用时 16 毫秒
1.
Snyder DA Chen Y Denissova NG Acton T Aramini JM Ciano M Karlin R Liu J Manor P Rajan PA Rossi P Swapna GV Xiao R Rost B Hunt J Montelione GT 《Journal of the American Chemical Society》2005,127(47):16505-16511
X-ray crystallography and NMR spectroscopy provide the only sources of experimental data from which protein structures can be analyzed at high or even atomic resolution. The degree to which these methods complement each other as sources of structural knowledge is a matter of debate; it is often proposed that small proteins yielding high quality, readily analyzed NMR spectra are a subset of those that readily yield strongly diffracting crystals. We have examined the correlation between NMR spectral quality and success in structure determination by X-ray crystallography for 159 prokaryotic and eukaryotic proteins, prescreened to avoid proteins providing polydisperse and/or aggregated samples. This study demonstrates that, across this protein sample set, the quality of a protein's [15N-1H]-heteronuclear correlation (HSQC) spectrum recorded under conditions generally suitable for 3D structure determination by NMR, a key predictor of the ability to determine a structure by NMR, is not correlated with successful crystallization and structure determination by X-ray crystallography. These results, together with similar results of an independent study presented in the accompanying paper (Yee, et al., J. Am. Chem. Soc., accompanying paper), demonstrate that X-ray crystallography and NMR often provide complementary sources of structural data and that both methods are required in order to optimize success for as many targets as possible in large-scale structural proteomics efforts. 相似文献
2.
Condensation of bis-(2-chloroethyl)phosphoramidic dichloride with 3′-amino-3′-deoxy-N,N-dimethyladenosine afforded the 2′,3′-cyclicphosphorodiamidate (III). By an improved synthesis, methyl 3-amino-3-deoxy-β-D-ribofuranoside was obtained as a model compound for conversion to the analogous 2,3-cyclicphosphorodiamidate (XII). Existence of the latter as two diastereomers due to phosphorus asymmetry was shown by nmr analysis, using comparison with the 5-(O-p-nitrobenzoate) (XIII) as a basis for assignments. 相似文献
3.
Abe K Abt I Acton PD Agnew G Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Baranko G Bardon O Battiston R Bazarko AO Bean A Belcinski RJ Ben-David R Benvenuti AC Biasini M Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Carr J Cassell R Castaldi R Castro A Cavalli-Sforza M Chadwick GB Chen L Church E Claus R Cohn HO Coller JA Cook V Cotton R 《Physical review letters》1993,71(16):2528-2532
4.
Dr. Anna Notaro Marta Jakubaszek Severin Koch Dr. Riccardo Rubbiani Dr. Orsolya Dömötör Dr. Éva A. Enyedy Mazzarine Dotou Dr. Fethi Bedioui Mickaël Tharaud Dr. Bruno Goud PD Dr. Stefano Ferrari Prof. Dr. Enzo Alessio Dr. Gilles Gasser 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(22):4997-5009
Cancer is one of the main causes of death worldwide. Chemotherapy, despite its severe side effects, is to date one of the leading strategies against cancer. Metal-based drugs present several potential advantages when compared to organic compounds and they have gained trust from the scientific community after the approval on the market of the drug cisplatin. Recently, we reported the ruthenium complex ([Ru(DIP)2(sq)](PF6) (where DIP is 4,7-diphenyl-1,10-phenantroline and sq is semiquinonate) with a remarkable potential as chemotherapeutic agent against cancer, both in vitro and in vivo. In this work, we analyse a structurally similar compound, namely [Ru(DIP)2(mal)](PF6), carrying the flavour-enhancing agent approved by the FDA, maltol (mal). To possess an FDA approved ligand is crucial for a complex, whose mechanism of action might include ligand exchange. Herein, we describe the synthesis and characterisation of [Ru(DIP)2(mal)](PF6), its stability in solutions and under conditions that resemble the physiological ones, and its in-depth biological investigation. Cytotoxicity tests on different cell lines in 2D model and on HeLa MultiCellular Tumour Spheroids (MCTS) demonstrated that our compound has higher activity than cisplatin, inspiring further tests. [Ru(DIP)2(mal)](PF6) was efficiently internalised by HeLa cells through a passive transport mechanism and severely affected the mitochondrial metabolism. 相似文献
5.
6.
A simple and efficient preparation of a number of hybrid linear‐branched PEG esters are described. The polymers are generated by direct coupling of PEG–carboxylic acids and a variety of pentaerythritol ethoxylates using carbon tetrabromide catalyst. 相似文献
7.
Dirk Schlüter Florian Kleemiss Dr. Malte Fugel Dr. Enno Lork Prof. Dr. Kunihisa Sugimoto PD Dr. Simon Grabowsky Prof. Dr. Jeffrey R. Harmer Dr. Matthias Vogt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(6):1335-1343
Derivatives of 1,2-dithienylethene (DTE) have superb photochromic properties due to an efficient reversible photocyclization reaction of their hexatriene structure and, thus, have application potential in materials for optoelectronics and (multi-responsive) molecular switches. Transition-metal complexes bearing switchable DTE motifs commonly incorporate their coordination site rather distant from the hexatriene system. In this work the redox active ligand 1,2-bis(2,5-dimethylthiophen-3-yl)ethane-1,2-dione is described, which reacts with [V(TMEDA)2Cl2] to give a rare non-oxido vanadium(IV) species 3(M,M/P,P) . This blue complex has two bidentate en-diolato ligands which chelate the VIV center and give rise to two five-membered metallacycles with the adjacent hexatriene DTE backbone bearing axial chirality. Upon irradiation with UVA light or prolonged heating in solution, the blue compound 3(M,M/P,P) converts into the purple atropisomer 4(para,M/para,P) . Both complexes were isolated and structurally characterized by single-crystal X-ray diffraction analysis (using lab source and synchrotron radiation). The antiparallel configuration (M or P helicity) present in both 3(M,M/P,P) and 4(para,M/para,P) is a prerequisite for (reversible) 6π cyclization reactions. A CW EPR spectroscopic study reveals the metalloradical character for 3(M,M/P,P) and 4(para,M/para,P) and indicates dynamic reversible cyclization of the DTE backbone in complex 3(M,M/P,P) at ambient temperature in solution. 相似文献
8.
Abstract. Continuous far-red light operating through phytochrome reduces the rate of hypocotyl lengthening by a factor of 8. Consonant with this was a reduction of up to 12% in the proportion of total cytoplasmic ribosomes present as polysomes. A 2% reduction was elicited by brief red light. Evidence is presented which argues against these changes arising from a change in extractability or nucleolytic activity. The speed of the response (1.5 h) is much slower than that for inhibition of lengthening (15 min). The data therefore indicate that phytochrome is unlikely to act by controlling the general rate of translation in this instance. 相似文献
9.
Several oxidation products of the retinoid retinylidene dimedone (RD) have been synthesized and characterized for biological testing in the expectation that they may be found as metabolites of RD. 相似文献
10.