Protein structure in anisotropic environments: Development of orientational constraints

Specification and Visualization of Anisotropic Interaction Tensors in Polypeptides and Numerical Simulations in Biological Solid-State NMR

“…In most cases the parameters describing both the magnitude and the orientation of the anisotropic parts of these tensors relative to the peptide plane (i.e., Ω P E ) exhibit only relatively small dependency on the residue type and the local structure [28][29][30]. While these minor variations may be very important probes for structure determination, the variation is sufficiently small that the typical values in almost any case will be sufficiently precise for simulation and optimization of pulse sequences for application on real structures.…”

Continuity conditions and torsion angles from ssNMR orientational restraints

“…Using (6), (10) where (11) (12) Using (5), (13) The bond orientation cosines and the scalar triple products involving backbone bond vectors of a diplane with B 0 in (13) can be written in terms of the degeneracies using the peptide plane geometry and (8) as: (14) where (15) with (16) The equations in (15) and (16) were derived in [17] assuming ideal peptide plane geometry [26]. Here, (σ 11 , σ 22 , σ 33 ) are the principal values of the 15 N chemical shift tensor written in the order of increasing magnitude, β is the angle between the NH bond and the principal axis vector σ 33 (≈ 17° [17]), and ν ‖ is the NH dipolar coupling constant.…”

“…Orientational restraints [10,16] from ssNMR form the basis of the recursive and gluing methods. These restraints give rise to degeneracies [11,12,13,17] in peptide plane orientations.…”

Correlation between NQR parameters and residue size of aliphatic amino acids and their dimers

“…Most of what is known about protein conformation has been obtained from water soluble proteins. Many such proteins are relatively easy to crystallize and therefore can also be studied by X-ray diffraction methods [4]. However, the relevance of the molecular structures in their crystalline phase for the biological molecules in aqueous solution is often questioned.…”