Figure 1
Figure 1. (A) Partial FoxB model obtained by experimental phasing before the CASP14 model became available. At this point the model could not be further improved and the project was stuck for a year. (B) Experimental phases with partial FoxB model (map shown at 1.2σ level).
At that point we were stuck with experimental phasing and submitted the FoxB sequence to CASP14. The model provided by AlphaFold2 (T1058TS427_3) resulted in a clear molecular replacement (MR) solution (TFZ: 18.9 / LLG: 324). We have also succeeded in finding a suitable crystal which diffracted to better than 3.5 Å, the crystal belonged to the P21212 space group and contained 2 molecules of FoxB in the asymmetric unit. The final resolution of the diffraction dataset after starANISO processing was 3.1 Å. Subsequent MR-SAD and several rounds of building/refinement using COOT19 and REFMAC20 further improved the model and resulted in a good electron density map for the entire protein. Anomalous difference maps were also used to validate the model (Fig. 2).