共查询到20条相似文献,搜索用时 15 毫秒
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Maria J. P. van Dongen Sybren S. Wijmenga Ramón Eritja Fernando Azorín Cornelis W. Hilbers 《Journal of biomolecular NMR》1996,8(2):207-212
Summary A new application of the HMBC experiment is presented that provides a useful means to discriminate between H2 and H8 proton resonances, to assign the base proton resonances to the various residue types and, most importantly, to correlate the H2 and H8 protons for adenine or inosine residues in natural abundance 13C fragments. The utility of this experiment is demonstrated for an unlabeled DNA 20-mer. Thanks to the obtained results, preliminary conclusions could be drawn regarding the molecular conformations of the non-canonical G/I-A base pairs in the hairpin formed by this fragment. 相似文献
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Jean-Michel Wieruszeski Jean-Claude Michalski Jean Montreuil Gérard Strecker 《Glycoconjugate journal》1989,6(2):183-194
400 MHz1H-NMR and 100 MHz13C-NMR spectra of a neutral octasaccharide and of a disialyldecasaccharide of theN-acetyllactosamine type were studied. The resonance assignments were made by combining multiple-relayed coherence-transfer chemical-shift-correlated spectroscopy (multiple-RELAY-COSY) and1H/13C-shift correlated 2D experiments. The complete analysis of the1H and13C spectra was performed. 相似文献
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Multiple-quantum 2D and 3D bi-directional HCNCH experiments are presented for the correlation of base and ribose protons/carbons in 13C/15N labeled HIV-1 TAR RNA. In both 2D and 3D experiments, the magnetization of H1 is transferred to H6/H8 and H1 through H1-C1-N1/9-C6/8-H6/8 and H1-C1-N1/9-C1-H1 pathways, and the magnetization of H6/8 is transferred to H1 and H6/8 through H6/8-C6/8-N1/9-C1-H1 and H6/8-C6/8-N1/9-C6/8-H6/8 pathways. Chemical shifts of four different nuclei (H1, C1, C6/8 and H6/8) are sampled in the 2D experiment. The correlation of base and ribose protons/carbons is established by the rectangular arrangement of crossover and out-and-back peaks in the proton/carbon correlated spectrum. The rectangular connections can be further resolved using the nitrogen dimension in a 1H/13C/15N 3D experiment. Furthermore, by taking advantage of the well separated chemical shifts of N1 (pyrimidine) and N9 (purine), the 2D spectrum can be simplified into two sub-spectra based on their base type. Both experiments were tested on a 13C/15N labeled 27-mer HIV-1 TAR RNA containing a UUCG hairpin loop. 相似文献
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Duraffourg N Choudens SO Fontecave M Loiseau L Barras F Marion D Blanchard L 《Journal of biomolecular NMR》2004,30(3):379-380
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1H, 13C, and 15N resonance assignments of Fusarium solani pisi cutinase and preliminary features of the structure in solution.
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J. J. Prompers A. Groenewegen R. C. Van Schaik H. A. Pepermans C. W. Hilbers 《Protein science : a publication of the Protein Society》1997,6(11):2375-2384
Essentially complete (96%) sequence-specific assignments were made for the backbone and side-chain 1H, 13C, and 15N resonances of Fusarium solani pisi cutinase, produced as a 214-residue heterologous protein in Escherichia coli, using heteronuclear NMR techniques. Three structural features were noticed during the assignment. (1) The secondary structure in solution corresponds mostly with the structure from X-ray diffraction, suggesting that both structures are globally similar. (2) The HN of Ala32 has a strongly upfield-shifted resonance at 3.97 ppm, indicative of an amide-aromatic hydrogen bond to the indole ring of Trp69 that stabilizes the N-terminal side of the parallel beta-sheet. (3) The NMR data suggest that the residues constituting the oxyanion hole are quite mobile in the free enzyme in solution, in contrast to the existence of a preformed oxyanion hole as observed in the crystal structure. Apparently, cutinase forms its oxyanion hole upon binding of the substrate like true lipases. 相似文献
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High-resolution heteronuclear NMR correlation experiments and strategies are proposed for the assignment of fully13 C/15N-labelled polypeptides in the solid state. By the combination of intra-residue and inter-residue13 C-15N correlation experiments with13 C-13C spin-diffusion studies, it becomes feasible to partially assign backbone and side-chain resonances in solid proteins. The performance of sequences using 15N instead of13 C detection is evaluated regarding sensitivity and resolution for a labelled dipeptide (L-Val-L-Phe). The techniques are used for a partial assignment of the 15N and 13C resonances in human ubiquitin. 相似文献
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Ingmar Sethson Ulf Edlund Tadeusz A. Holak Alfred Ross Bengt-Harald Jonsson 《Journal of biomolecular NMR》1996,8(4):417-428
Summary The backbone NMR resonances of human carbonic anhydase I (HCA I) have been assigned. This protein is one of the largest monomeric proteins assigned so far. The assignment was enabled by a combination of 3D triple-resonance experiments and extensive use of amino acid-specific 15N-labeling. The obtained resonance assignment has been used to evaluate the secondary structure elements present in solution. The solution structure appears to be very similar to the crystal structure, although some differences can be observed. Proton-deuteron exchange experiments have shown that the assignments provide probes that can be used in future folding studies of HCA I.The chemical shift data have been deposited in the BioMagResBank in Madison, WI, U.S.A. 相似文献
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Triple-resonance two-dimensional H6/H5(C4N)H and C6/C5(C4N)H experiments are described that provide through-bond H6/H5 or C6/C5 to imino/amino correlations in pyrimidine bases in 13C,15N-labeled RNA. The experiments simultaneously transfer H6/H5 magnetization by an INEPT step to the C6/C5 nuclei and by homonuclear CC- and heteronuclear CN-TOCSY steps via the intervening C4 nucleus to the N3/N4 nuclei and then by a reverse INEPT step to the imino/amino hydrogens. The sensitivity of these experiments is high as demonstrated using a 30-nucleotide pyrimidine rich RNA at a concentration of 0.9 mM at temperatures of 10°C and 25°C. This indicates the general applicability of the experiments and the possibility to obtain correlations for imino resonances in non-canonical regions of the target RNA. 相似文献