Crystallization and preliminary X-ray analysis of the complex of the first von Willebrand type C domain bound to bone morphogenetic protein 2.

Crossveinless 2 (CV2) is a member of the chordin family, a protein superfamily that modulates the activity of bone morphogenetic proteins such as BMP2. The BMPs represent a large group of secreted proteins that control many steps during embryonal development and in tissue and organ homeostasis in the adult organism. The gene encoding the first von Willebrand type C domain (VWC1) of CV2 was cloned, expressed in Escherichia coli and purified to homogeneity. The binary complex of CV2 VWC1 and BMP2 was purified and subjected to crystallization. Crystals of SeMet-labelled proteins were obtained in two different forms belonging to the tetragonal space groups P4(1)2(1)2 and I4(1), with unit-cell parameters a = b = 86.7, c = 139.2 A and a = b = 83.7, c = 139.6 A, respectively. Initial analysis suggests that a complete binary complex consisting of one BMP2 dimer bound to two CV2 VWC1 domains is present in the asymmetric unit.