Purification, crystallization and preliminary data analysis of the ligand–receptor complex of the growth and differentiation factor 5 variant R57A (GDF5R57A) and BMP receptor IA (BRIA)

The ligand–receptor complex of human growth and differentiation factor 5 (GDF5) bound to the extracellular domain of human BMP type IA receptor (BRIA_EC) can be crystallized as long as the GDF5 variant R57A, which exhibits an enhanced affinity for BRIA, is employed. The binary ligand–receptor complex of human growth and differentiation factor 5 (GDF5) bound to its type I receptor BMP receptor IA (BRIA) was prepared and crystallized. By utilizing the GDF5 variant R57A, which exhibits a high affinity in the subnanomolar range for BRIA, the binary complex of GDF5R57A bound to the extracellular domain of BRIA could be produced and purified. Crystals of this complex belonged to a monoclinic space group: either I2, with unit-cell parameters a = 63.81, b = 62.85, c = 124.99 Å, β = 95.9°, or C2, with unit-cell parameters a = 132.17, b = 62.78, c = 63.53 Å, β = 112.8°