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For a fully oriented molecule, the dipolar coupling for an 1 H-15 N amide group would be over 20 kHz, and a pair of protons separated by 5 Å would have up to ~1 kHz coupling. However the degree of alignment achieved by applying magnetic field is so low that the largest 1 H- 15 N or 1 H- 13 C dipolar couplings are <5 Hz. [ 19 ]
Magnetic dipole–dipole interaction, also called dipolar coupling, refers to the direct interaction between two magnetic dipoles.Roughly speaking, the magnetic field of a dipole goes as the inverse cube of the distance, and the force of its magnetic field on another dipole goes as the first derivative of the magnetic field.
The dipolar coupling is commonly used in solid state NMR and provides information about the relative orientation of the bond vectors relative to a single global reference frame. Typically the orientation of the N-H vector is probed in an HSQC-like experiment. Initially, residual dipolar couplings were used for refinement of previously ...
The bulk of the data deposited at the BMRB consists of over 11,900 entries containing 1 H, 13 C, 15 N and 31 P assigned chemical shifts and coupling constants of peptides, proteins and nucleic acids. [5] Other derived data like residual dipolar couplings (RDC), relaxation parameters, NOE values, order parameters and hydrogen exchange rates are ...
The software package was later extended to include additional NMR conformational parameters, such as Residual Dipolar Couplings , [2] NOE distance restraints, [3] pseudocontact chemical shifts [4] and restraints derived from homologous proteins. [5]
The mechanisms of nuclear-spin energy-coupling have been extensively characterized and are described in the following articles: Angular momentum coupling, Magnetic dipole–dipole interaction, J-coupling, Residual dipolar coupling, Nuclear Overhauser effect, Spin–spin relaxation, and Spin saturation transfer. Alternatively, some nuclei in a ...
The spin interaction that is usually employed for structural analyses via solid state NMR spectroscopy is the magnetic dipolar interaction. [8] Additional knowledge about other interactions within the studied system like the chemical shift or the electric quadrupole interaction can be helpful as well, and in some cases solely the chemical shift has been employed as e.g. for zeolites. [9]
However, long-range orientation information can be obtained through residual dipolar coupling experiments in a medium which imposes a weak alignment on the nucleic acid molecules. [1] [2] Recently, solid-state NMR methodology has been introduced for the structure determination of nucleic acids. [6]