Table 3. Comparison of the phasing statistics for the B3C and I3C data sets.

The mean phase error and mean map correlation coefficient compare the first experimental map obtained after density modification with SHELXE with the final refined map (SHELXL). MAD phasing with B3C results in better starting phases: the mean phase error is lower, the mean map correlation coefficient is higher and more residues can be traced compared with the SAD data set.

	B3C (MAD)	I3C (SAD)
SHELXD CC/CC(weak)	46.6/37.6	52.0/32.5
Mean phase error ()	31.2	36.9
Mean map CC	0.861	0.786
Residues traced (ARP/wARP)	272/279 (97.5%)	267/279 (95.7%)