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Site‐Specific Isotope‐Labeling of Inosine Phosphoramidites and NMR Analysis of an Inosine‐Containing RNA Duplex 下载免费PDF全文
Dr. Andre Dallmann Dr. Alexander V. Beribisky Dr. Felix Gnerlich Martin Rübbelke Dr. Stefan Schiesser Prof. Dr. Thomas Carell Prof. Dr. Michael Sattler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(43):15350-15359
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Structure and Metabolic‐Flow Analysis of Molecular Complexity in a 13C‐Labeled Tree by 2D and 3D NMR 下载免费PDF全文
Takanori Komatsu Risa Ohishi Amiu Shino Prof. Dr. Jun Kikuchi 《Angewandte Chemie (International ed. in English)》2016,55(20):6000-6003
Improved signal identification for biological small molecules (BSMs) in a mixture was demonstrated by using multidimensional NMR on samples from 13C‐enriched Rhododendron japonicum (59.5 atom%) cultivated in air containing 13C‐labeled carbon dioxide for 14 weeks. The resonance assignment of 386 carbon atoms and 380 hydrogen atoms in the mixture was achieved. 42 BSMs, including eight that were unlisted in the spectral databases, were identified. Comparisons between the experimental values and the 13C chemical shift values calculated by density functional theory supported the identifications of unlisted BSMs. Tracing the 13C/12C ratio by multidimensional NMR spectra revealed faster and slower turnover ratios of BSMs involved in central metabolism and those categorized as secondary metabolites, respectively. The identification of BSMs and subsequent flow analysis provided insight into the metabolic systems of the plant. 相似文献
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《Analytical letters》2012,45(14):1209-1219
Abstract A procedure for automating the analysis of humic substances in natural fresh water samples is described. Thirty samples are analysed per hour in a working range of 0.5 mg/l to 20 mg/l. Significant interferences observed in other methods are eliminated. 相似文献
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Gwendal Kervern Anthony D'Aléo Dr. Loïc Toupet Dr. Olivier Maury Dr. Lyndon Emsley Prof. Guido Pintacuda Dr. 《Angewandte Chemie (International ed. in English)》2009,48(17):3082-3086
Shifts for crystals : Solid‐state NMR spectroscopy can be used for structure determination of microcrystalline paramagnetic solids at natural isotopic abundance. The protocol makes use of paramagnetic effects, measured on suitably recorded 1H NMR spectra, to define the conformation of a molecule in the lattice and the intermolecular packing in the solid phase. The method is illustrated with a family of lanthanide compounds (see picture).
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Untangling a Repetitive Amyloid Sequence: Correlating Biofilm‐Derived and Segmentally Labeled Curli Fimbriae by Solid‐State NMR Spectroscopy 下载免费PDF全文
Dr. Tobias Schubeis Puwei Yuan Dr. Mumdooh Ahmed Dr. Madhu Nagaraj Dr. Barth‐Jan van Rossum Dr. Christiane Ritter 《Angewandte Chemie (International ed. in English)》2015,54(49):14669-14672
Curli are functional bacterial amyloids produced by an intricate biogenesis machinery. Insights into their folding and regulation can advance our understanding of amyloidogenesis. However, gaining detailed structural information of amyloids, and their tendency for structural polymorphisms, remains challenging. Herein we compare high‐quality solid‐state NMR spectra from biofilm‐derived and recombinantly produced curli and provide evidence that they adopt a similar, well‐defined β‐solenoid arrangement. Curli subunits consist of five sequence repeats, resulting in severe spectral overlap. Using segmental isotope labeling, we obtained the unambiguous sequence‐specific resonance assignments and secondary structure of one repeat, and demonstrate that all repeats are most likely structurally equivalent. 相似文献
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Assaf Tal Boaz Shapira Dr. Lucio Frydman Prof. 《Angewandte Chemie (International ed. in English)》2009,48(15):2732-2736
Scan and deliver : By combining imaging‐based spectral/spatial 2D radiofrequency manipulations (see scheme, left) with Hadamard‐weighting principles, 2D NMR spectra can be retrieved within a single scan (right). This approach can give homo‐ or heteronuclear correlations with an enhanced sensitivity over conventional ultrafast 2D NMR spectroscopy.
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Enhancing the Sensitivity of CPMG Relaxation Dispersion to Conformational Exchange Processes by Multiple‐Quantum Spectroscopy 下载免费PDF全文
Dr. Tairan Yuwen Dr. Pramodh Vallurupalli Prof. Lewis E. Kay 《Angewandte Chemie (International ed. in English)》2016,55(38):11490-11494
A triple‐quantum 1H Carr–Purcell–Meiboom–Gill NMR relaxation dispersion experiment is presented that uses methyl group probes as reporters of conformational exchange in highly deuterated, methyl‐protonated proteins. Significantly larger dispersion profiles, by as much as a factor of nine, can be obtained relative to single‐quantum approaches, thus offering very significant advantages in applications involving interconverting conformers with only small changes in structure or in studies of rare states that are at very low populations. Applications to a number of protein systems are presented where the utility of the method, including its improved sensitivity to chemical exchange processes, is established. 相似文献
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Differentially Isotope‐Labeled Nucleosomes To Study Asymmetric Histone Modification Crosstalk by Time‐Resolved NMR Spectroscopy 下载免费PDF全文
Dr. Stamatios Liokatis Dr. Rebecca Klingberg Prof. Dr. Song Tan Prof. Dr. Dirk Schwarzer 《Angewandte Chemie (International ed. in English)》2016,55(29):8262-8265
Post‐translational modifications (PTMs) of histones regulate chromatin structure and function. Because nucleosomes contain two copies each of the four core histones, the establishment of different PTMs on individual “sister” histones in the same nucleosomal context, that is, asymmetric histone PTMs, are difficult to analyze. Here, we generated differentially isotope‐labeled nucleosomes to study asymmetric histone modification crosstalk by time‐resolved NMR spectroscopy. Specifically, we present mechanistic insights into nucleosomal histone H3 modification reactions in cis and in trans, that is, within individual H3 copies or between them. We validated our approach by using the H3S10phK14ac crosstalk mechanism, which is mediated by the Gcn5 acetyltransferase. Moreover, phosphorylation assays on methylated substrates showed that, under certain conditions, Haspin kinase is able to produce nucleosomes decorated asymmetrically with two distinct types of PTMs. 相似文献
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Functional Dynamics of Deuterated β2‐Adrenergic Receptor in Lipid Bilayers Revealed by NMR Spectroscopy 下载免费PDF全文
Dr. Yutaka Kofuku Dr. Takumi Ueda Junya Okude Yutaro Shiraishi Keita Kondo Takuya Mizumura Shiho Suzuki Prof. Dr. Ichio Shimada 《Angewandte Chemie (International ed. in English)》2014,53(49):13376-13379
G‐protein‐coupled receptors (GPCRs) exist in conformational equilibrium between active and inactive states, and the former population determines the efficacy of signaling. However, the conformational equilibrium of GPCRs in lipid bilayers is unknown owing to the low sensitivities of their NMR signals. To increase the signal intensities, a deuteration method was developed for GPCRs expressed in an insect cell/baculovirus expression system. The NMR sensitivities of the methionine methyl resonances from the β2‐adrenergic receptor (β2AR) in lipid bilayers of reconstituted high‐density lipoprotein (rHDL) increased by approximately 5‐fold upon deuteration. NMR analyses revealed that the exchange rates for the conformational equilibrium of β2AR in rHDLs were remarkably different from those measured in detergents. The timescales of GPCR signaling, calculated from the exchange rates, are faster than those of receptor tyrosine kinases and thus enable rapid neurotransmission and sensory perception. 相似文献
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Dr. Elwin A. W. van der Cruijsen Dr. Eline J. Koers Claire Sauvée Dr. Raymond E. Hulse Dr. Markus Weingarth Dr. Olivier Ouari Prof. Dr. Eduardo Perozo Prof. Dr. Paul Tordo Prof. Dr. Marc Baldus 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(37):12971-12977
Dynamic nuclear polarization (DNP) has been shown to greatly enhance spectroscopic sensitivity, creating novel opportunities for NMR studies on complex and large molecular assemblies in life and material sciences. In such applications, however, site‐specificity and spectroscopic resolution become critical factors that are usually difficult to control by current DNP‐based approaches. We have examined in detail the effect of directly attaching mono‐ or biradicals to induce local paramagnetic relaxation effects and, at the same time, to produce sizable DNP enhancements. Using a membrane‐embedded ion channel as an example, we varied the degree of paramagnetic labeling and the location of the DNP probes. Our results show that the creation of local spin clusters can generate sizable DNP enhancements while preserving the intrinsic benefits of paramagnetic relaxation enhancement (PRE)‐based NMR approaches. DNP using chemical labeling may hence provide an attractive route to introduce molecular specificity into DNP studies in life science applications and beyond. 相似文献
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Hartmut Oschkinat Thomas Müller Thorsten Dieckmann 《Angewandte Chemie (International ed. in English)》1994,33(3):277-293
Structural biology has made important contributions to the understanding of biological processes. In recent years an increasing amount of structural information has also been derived from NMR spectroscopic studies, often with special emphasis on dynamic aspects. The introduction of three- and four-dimensional techniques has greatly simplified protein structure determination by NMR Spectroscopy, which has in fact become routine. In the past it was more of an art to interpret the complicated NOESY spectra of proteins, but the application of three-dimensional techniques now makes the interpretation of protein spectra straightforward. In this review we discuss the most important multidimensional NMR techniques along with suitable applications. The emphasis is put less on the discussion of individual pulse sequences than on their application to the structure determination of proteins. 相似文献
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An Isotope‐Coded Fluorogenic Cross‐Linker for High‐Performance Target Identification Based on Photoaffinity Labeling 下载免费PDF全文
Dr. Takenori Tomohiro Shota Morimoto Toshiya Shima Dr. Junya Chiba Dr. Yasumaru Hatanaka 《Angewandte Chemie (International ed. in English)》2014,53(49):13502-13505
A photoaffinity labeling (PAL)‐based method for the rapid identification of target proteins is presented in which a high‐performance chemical tag, an isotope‐coded fluorescent tag (IsoFT), can be attached to the interacting site by irradiation. Labeled peptides can be easily distinguished among numerous proteolytic digests by sequential detection with highly sensitive fluorescence spectroscopy and mass spectrometry. Subsequent MS/MS analysis provides amino acid sequence information with a higher depth of coverage. The combination of PAL and heterogeneous target‐selecting techniques significantly reduces the amount of time and protein required for identification. An additional photocleavable moiety successfully accelerated proteomic analysis using cell lysate. This method is a widely applicable approach for the rapid and accurate identification of interacting proteins. 相似文献
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Structural Revision and Elucidation of the Biosynthesis of Hypodoratoxide by 13C,13C COSY NMR Spectroscopy 下载免费PDF全文
Lena Barra Dr. Kerstin Ibrom Prof. Dr. Jeroen S. Dickschat 《Angewandte Chemie (International ed. in English)》2015,54(22):6637-6640
Feeding of (2,3,4,5,6‐13C5)mevalonolactone to the fungus Hypomyces odoratus resulted in a completely labeled sesquiterpene ether. The connectivity of the carbon atoms was easily deduced from a 13C,13C COSY spectrum, revealing a structure that was different from the previously reported structure of hypodoratoxide, even though the reported 13C NMR data matched. A structural revision of hypodoratoxide is thus presented. Its absolute configuration was tentatively assigned from its co‐metabolite cis‐dihydroagarofuran. Its biosynthesis was investigated by feeding of (3‐13C)‐ and (4,6‐13C2)mevalonolactone, which gave insights into the complex rearrangement of the carbon skeleton during terpene cyclization by analysis of the 13C,13C couplings. 相似文献
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Bradley Man Xun‐Cheng Su Dr. Haobo Liang Dr. Shane Simonsen Dr. Thomas Huber Dr. Barbara A. Messerle Prof. Gottfried Otting Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(12):3827-3832
Paramagnetic effects from lanthanide ions present powerful tools for protein studies by nuclear magnetic resonance (NMR) spectroscopy provided that the lanthanide can be site‐specifically and rigidly attached to the protein. A new, particularly small and rigid lanthanide‐binding tag, 3‐mercapto‐2,6‐pyridinedicarboxylic acid (3MDPA), was synthesized and attached to two different proteins via a disulfide bond. The complexes of the N‐terminal domain of the E. coli arginine repressor (ArgN) with seven different paramagnetic lanthanide ions and Co2+ were analyzed in detail by NMR spectroscopy. The magnetic susceptibility anisotropy (Δχ) tensors and metal position were determined from pseudocontact shifts. The 3MDPA tag generated very different Δχ tensor orientations compared to the previously studied 4‐mercaptomethyl‐DPA tag, making it a highly complementary and useful tool for protein NMR studies. 相似文献