Table 3. Structure solution and refinement.

Values in parentheses are for the outer shell.

	Chom-18Br	Chom-18	Hpar-18
No. of reflections, working set	2259	1790	1629
No. of reflections, test set	108	95	94
Final R work	0.239	0.242	0.264
Final R free	0.292	0.279	0.312
Final R all	0.239	0.250	0.272
No. of non-H atoms
DNA	365	365	365
Ion	2	3	2
Total	367	368	367
R.m.s. deviations
Bonds (Å)	0.010	0.011	0.010
Angles (°)	1.21	1.09	1.02
Average B factors (Å2)	120	108	122
NtC analysis
Assigned	15	15	14
Outliers	2	2	3
PDB code	6ror	6ros	6rou