Table 5.
Overview of intermolecular distance measurements. Where applicable, distances between non-identical sites (i.e. C’-Cα and C’-N contacts) only reflect the shorter distance of the two in-equivalent pairings that characterize intra-sheet contacts (see e.g. Fig 6e). X-ray crystallographic distances are based on PDB files 1YJP and 2OMM, respectively (4, 5). Note that the systematic errors listed reflect the assumptions made in the analysis, most notably assuming a lack of (undetermined) dynamical averaging and sometimes does not account for all multispin interactions (see text and SI for specific details). The presence of signification molecular motion would imply shorter actual distances than listed below.
| Fibrils by MAS NMR | X-ray crystallography | |||||
|---|---|---|---|---|---|---|
| intermolecular distance |
MAS NMR Experiment |
conformer # 1 |
conformer # 2 |
conformer # 3 |
monoclinic crystals |
orthorhombic crystals |
| G7C’-G7C’ | DRAWS1) | 4.9±1.0Å | 4.9±1.0Å | 4.9±1.0Å | 4.9 | 4.9 |
| G7C’-G7Cα | R2W | 4.5±1.0Å | 4.85±1.0Å | 4.7±1.0Å | 3.9 | 3.9 |
| G7C’-G7N | REDOR2) | 4.5±0.8Å | 4.5±0.6Å | 5.0±0.8Å | 3.9 | 4.0 |
Analysis assumed equivalent distance for all three fibril forms.
Results based on simple model with single 13C-15N coupling.