A typical molecular ion mass spectrum consists of a sum of signals from species of various possible isotopic compositions. Only the monoisotopic peak (e.g., all carbons are 12C; all nitrogens are 14N, etc.) has a unique elemental composition. Every other isotope peak at approximately integer multiples of approximately 1 Da higher in nominal mass represents a sum of contributions from isotope co...

Efficiently hyperpolarizing proton-dense molecular solids through dynamic nuclear polarization (DNP) solid-state NMR is still an unmet challenge. Polarizing agents (PAs) developed so far do not perform well on proton-rich systems, such as organic microcrystals and biomolecular assemblies. Herein we introduce a new PA, cAsymPol-POK, report outstanding hyperpolarization efficiency 12.76 kDa U-13C...

The secondary structure of human recombinant interleukin-4 (IL-4) has been investigated by three-dimensional (3D) 15N- and 13C-edited nuclear Overhauser (NOE) spectroscopy on the basis of the 1H, 15N, and 13C assignments presented in the preceding paper [Powers, R., Garrett, D. S., March, C. J., Frieden, E. A., Gronenborn, A. M., & Clore, G. M. (1992) Biochemistry (preceding paper in this issue...

A combination of three heteronuclear three-dimensional NMR experiments tailored for sequential resonance assignments in uniformly 15N, 13C-labeled flexible polypeptide chains is described. The 3D (H)N(CO-TOCSY)NH, 3D (H)CA(CO-TOCSY)NH and 3D (H)CBCA(CO-TOCSY)NH schemes make use of the favorable 15N chemical shift dispersion in unfolded polypeptides, exploit the slow transverse 15N relaxation ra...

Determining the accurate chemical structures of synthesized compounds is essential for biomedical studies and computer-assisted drug design. The unequivocal determination of N-adamantylation or N-arylation site(s) in nitrogen-rich heterocycles, characterized by a low density of hydrogen atoms, using NMR methods at natural isotopic abundance is difficult. In these compounds, the heterocyclic moi...

We report here the backbone assignment of Rv1567c, an integral membrane protein from Mycobacterium tuberculosis. The backbone resonance assignments were determined based on triple-resonance experiments with uniformly [13C,15N]-labeled protein in LMPG detergent micelles.

In this work, we carried out an extended verification of the 13C–15N spin–spin coupling constants as a new structural indicator nitrogen-containing organic compounds. regard, performed quantum-chemical calculation (B3LYP with basis set 6-311++G(2df,2p)) for representative sample 193 couplings currently known literature experimental data on them in conformationally rigid and structurally fixed C...

Four new 1,5-benzothiazepines were synthesized by reaction of o-aminothiophenol with curcumin and curcuminoid β-diketones, in methanol acetic acid. The mechanism involves a Michael addition on the CC double bond affording benzothiazepine two pendant groups, an aryl group adjacent to sulfur atom 1-phenylethanone NH seven membered ring. 1D 2D multinuclear NMR (1H, 13C, 15N, 119F) solution 13C 15N...

DFT calculations were applied to evaluate the electronic and magnetic properties of zigzag BC2Nnanotubes based on the 13C, 15N, and 11B NMR parameters and natural charge analysis. Weconsidered three types of zigzag nanotubes, ZZ-1, ZZ-2, and ZZ-3 (n, 0) with n = 8, 12, and 14. Theobtained results indicated the divisions of the electrostatic environments around C nuclei into a fewlayers, consist...

We describe a method for determining the torsion angle φ in peptides. The technique is based on the measurement of the relative orientation of the N-HN and CR-HR bonds, which is manifested in the rotational sideband spectrum of the sum and difference of the two corresponding dipolar couplings. The method exploits 15N-13C double-quantum and zero-quantum coherences, which evolve simultaneously un...