Table 3.
Torsion angles [°] in nucleotides of the major A- and B-forms
| α | β | γ | δ | ɛ | ζ | χ | N | |
|---|---|---|---|---|---|---|---|---|
| Canonical A-form (AI) | 294.8 ± 0.9 | 172.7 ± 1.0 | 54.3 ± 0.9 | 82.1 ± 0.7 | 205.6 ± 1.0 | 285.4 ± 0.7 | 200.5 ± 1.0 | 180 |
| AII | 145.6 ± 2.3 | 191.9 ± 2.0 | 182.8 ± 1.7 | 85.0 ± 1.4 | 197.0 ± 2.0 | 289.2 ± 1.7 | 203.4 ± 1.1 | 49 |
| Canonical B-form (BI) | 299.0 ± 0.9 | 179.3 ± 1.0 | 48.4 ± 0.6 | 132.8 ± 1.0 | 181.7 ± 1.0 | 263.2 ± 0.8 | 250.3 ± 1.1 | 418 |
| BII | 292.6 ± 1.3 | 143.1 ± 1.3 | 46.0 ± 0.9 | 143.0 ± 0.9 | 251.1 ± 2.1 | 168.0 ± 1.4 | 277.8 ± 1.4 | 187 |
The data were obtained through the analysis of 118 naked (noncomplexed) DNA structures from Dataset 3 (Table 1). The confidence intervals for the mean values of the torsion angles were computed under the assumption that the angles at the 95% confidence level are distributed normally. N is the number of observations of each conformer, AI corresponds to Cluster 8, AII to Cluster 19, BI to Cluster 54 and BII to Cluster 98.