Table 1.
Statistics from the crystallographic analysis
| Native | Derivative 1*
|
Derivative 2*
|
||||
|---|---|---|---|---|---|---|
| Data set 1 | Data set 2 | Data set 3 | Data set 4 | Data set 5 | ||
| Data collection | ||||||
| Observed reflections | 126,746 | 74,611 | 86,629 | 47,898 | 33,420 | 56,366 |
| Unique reflections | 19,034 | 20,631 | 21,289 | 22,676 | 17,871 | 22,863 |
| Completeness, % | 77.4† | 96.0 | 97.6 | 92.8 | 70.6 | 95.6 |
| Rmerge, % | 12.8 | 15.2 | 11.0 | 12.0 | 15.5 | 13.1 |
| Mean I/σ | 7.0 | 5.1 | 8.4 | 6.0 | 4.0 | 5.0 |
| MIR analysis | ||||||
| Resolution, Å | 40–3.1 | |||||
| Mean isomorphous difference, % | 14.7 | 12.6 | 20.0 | 21.8 | 18.6 | |
| Phasing power | 1.48 | 1.57 | 1.61 | 1.79 | 1.93 | |
| Cullis R-factor | 0.82 | 0.81 | 0.82 | 0.75 | 0.74 | |
| Mean overall figure of merit | 0.47 | |||||
| Refinement | ||||||
| Resolution, Å | 8–3.1 | |||||
| R-factor, % | 29.7 | |||||
| Free R-factor, % | 33.7 | |||||
| Reflections with |F| > 2σ | 17,027 | |||||
| Nonhydrogen atoms | 5,474 | |||||
| Bond lengths RMS deviation, Å | 0.02 | |||||
| Bond angles RMS deviation, degrees | 2.35 | |||||
*
Positions of 5IdU substitution in derivative 1 are T73, T76, and T93′, and in derivative 2 are T73, T76, and T88′.
†
After local filtering with an Ihkl/σhkl cutoff of 1.0 to eliminate regions of unreliable data. Crystallographic R-factor = ∑ |Fobs − Fcalc|/∑|Fobs|, calculated using anisotropically sharpened data.