From Topology to High Resolution Membrane Protein Structures

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

“…6i. In this discussion, however, it is important to realize that there might be two origins to the distortions of the simulated PISA wheels as pointed out by Cross et al [73]. One is local variations in the torsion angles of the true molecule structure, another is uncertainties in the measured molecular structure (i.e., in the PDB file) from which the present PISA wheels are calculated.…”

2D solid state NMR spectral simulation of 310, α, and π-helices

“…At the same time, this remarkable sensitivity could blur the PISA wheel pattern if there is non-uniformity among the set of /, w angles. As previously shown, low resolution crystal structures (>2.0 A resolution) cannot be used for PISA wheel predictions, whereas higher resolution (<2.0 A resolution) structures show clear PISA wheels due to the improvement in the atomic coordinates [21,34]. The high resolution membrane protein structures show remarkable homogeneity in the a-helical torsion angles except at the site of a kink, p-bulge, etc.…”