Crystallization and preliminary X-ray analysis of the cardiac transcription factor complex of NKX2.5 and TBX5 with DNA.

Heart development depends on timely expression of genes regulated by combinatorial interactions of master cardiac transcription factors. To elucidate the molecular basis of their interactions, a ternary complex of cardiac transcription factors, NKX2.5 and TBX5, and their target DNA was studied using X-ray crystallography. Here, the purification, crystallization and preliminary X-ray crystallographic analyses of the NKX2.5 homeodomain and TBX5 DNA-binding domain complex with a DNA element from the -252 promoter region of the atrial natriuretic factor are reported. The crystal diffracted to 2.88 Å resolution and belonged to space group P21, with unit-cell parameters a = 69.30, b = 77.78, c = 77.60 Å, β = 108.31°. Two sets of ternary complexes are present in an asymmetric unit with a solvent content of 54%.